630 lines
29 KiB
Text
630 lines
29 KiB
Text
<!-- Copyright (c) 2001 The FreeBSD Documentation Project
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Redistribution and use in source (SGML DocBook) and 'compiled' forms
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1. Redistributions of source code (SGML DocBook) must retain the above
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THIS DOCUMENTATION IS PROVIDED BY THE FREEBSD DOCUMENTATION PROJECT "AS
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IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NIK CLAYTON BE LIABLE FOR ANY
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POSSIBILITY OF SUCH DAMAGE.
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$FreeBSD$
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-->
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<!DOCTYPE article PUBLIC "-//FreeBSD//DTD DocBook V4.1-Based Extension//EN" [
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<!ENTITY % man PUBLIC "-//FreeBSD//ENTITIES DocBook Manual Page Entities//EN">
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%man;
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<!ENTITY legalnotice SYSTEM "../../share/sgml/legalnotice.sgml">
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]>
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<article>
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<articleinfo>
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<title>FreeBSD and Solid State Devices</title>
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<authorgroup>
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<author>
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<firstname>John</firstname>
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<surname>Kozubik</surname>
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<affiliation>
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<address><email>john@kozubik.com</email></address>
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</affiliation>
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</author>
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</authorgroup>
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<pubdate>$FreeBSD$</pubdate>
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<copyright>
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<year>2001</year>
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<holder>The FreeBSD Documentation Project</holder>
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</copyright>
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&legalnotice;
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<abstract>
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<para>This article covers the use of solid state disk devices in FreeBSD
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to create embedded systems.</para>
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<para>Embedded systems have the advantage of increased stability due to
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the lack of integral moving parts (hard drives). Account must be
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taken, however, for the generally low disk space available in the
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system and the durability of the storage medium.</para>
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<para>Specific topics to be covered include the types and attributes of
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solid state media suitable for disk use in FreeBSD, kernel options
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that are of interest in such an environment, the
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<filename>rc.diskless</filename> mechanisms that automate the
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initialization of such systems and the need for read-only filesystems,
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and building filesystems from scratch. The article will conclude
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with some general strategies for small and read-only FreeBSD
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environments.</para>
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</abstract>
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</articleinfo>
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<sect1 id="intro">
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<title>Solid State Disk Devices</title>
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<para>The scope of this article will be limited to solid state disk
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devices made from flash memory. Flash memory is a solid state memory
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(no moving parts) that is non-volatile (the memory maintains data even
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after all power sources have been disconnected). Flash memory can
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withstand tremendous physical shock and is reasonably fast (the flash
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memory solutions covered in this article are slightly slower than a EIDE
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hard disk for write operations, and much faster for read operations).
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One very important aspect of flash memory, the ramifications of which
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will be discussed later in this article, is that each sector has a
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limited rewrite capacity. You can only write, erase, and write again to
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a sector of flash memory a certain number of times before the sector
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becomes permanently unusable. Although many flash memory products
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automatically map bad blocks, and although some even distribute write
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operations evenly throughout the unit, the fact remains that there
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exists a limit to the amount of writing that can be done to the device.
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Competitive units have between 1,000,000 and 10,000,000 writes per
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sector in their specification. This figure varies due to the
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temperature of the environment.</para>
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<para>Specifically, we will be discussing ATA compatible compact-flash
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units and the M-Systems Disk-On-Chip flash memory unit. ATA compatible
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compact-flash cards are quite popular as storage media for digital
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cameras. Of particular interest is the fact that they pin out directly
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to the IDE bus and are compatible with the ATA command set. Therefore,
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with a very simple and low-cost adaptor, these devices can be attached
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directly to an IDE bus in a computer. Once implemented in this manner,
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operating systems such as FreeBSD see the device as a normal hard disk
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(albeit small). The M-Systems Disk-On-Chip product is based on the same
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underlying flash memory technology as ATA compatible compact-flash
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cards, but resides in a DIP form factor and is not ATA compatible. To
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use such a device, not only must you install it on a motherboard that
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has a Disk-On-Chip socket, you must also build the `fla` driver into any
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FreeBSD kernel you wish to use it with. Further, there is critical,
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manufacturer-specific data residing in the boot sector of this device,
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so you must take care not to install the FreeBSD (or any other) boot
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loader when using this.</para>
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<para>Other solid state disk solutions do exist, but their expense,
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obscurity, and relative unease of use places them beyond the scope of
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this article.</para>
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</sect1>
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<sect1 id="kernel">
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<title>Kernel Options</title>
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<para>A few kernel options are of specific interest to those creating
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an embedded FreeBSD system.</para>
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<para>First, all embedded FreeBSD systems that use flash memory as system
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disk will be interested in memory disks and memory filesystems. Because
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of the limited number of writes that can be done to flash memory, the
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disk and the filesystems no the disk will most likely be mounted
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read-only. In this environment, filesystems such as
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<filename>/tmp</filename> and <filename>/var</filename> are mounted as
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memory filesystems to allow the system to create logs and update
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counters and temporary files. Memory filesystems are a critical
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component to a successful solid state FreeBSD implementation.</para>
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<para>You should make sure the following lines exist in your kernel
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configuration file:</para>
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<programlisting>options MFS # Memory Filesystem
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options MD_ROOT # md device usable as a potential root device
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pseudo-device md # memory disk</programlisting>
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<para>Second, if you will be using the M-Systems Disk-On-Chip product, you
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must also include this line:</para>
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<programlisting>device fla0 at isa?</programlisting>
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</sect1>
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<sect1 id="ro-fs">
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<title><filename>rc.diskless</filename> and Read-Only Filesystems</title>
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<para>The post-boot initialization of an embedded FreeBSD system is
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controlled by <filename>/etc/rc.diskless2</filename>
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(<filename>/etc/rc.diskless1</filename> is for BOOTP diskless boot).
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This initialization script is invoked by placing a line in
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<filename>/etc/rc.conf</filename> as follows:</para>
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<programlisting>diskless_mount=/etc/rc.diskless2</programlisting>
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<para><filename>rc.diskless2</filename> mounts <filename>/var</filename>
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as a memory filesystem, makes a configurable list of directories in
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<filename>/var</filename> with the &man.mkdir.1; command, changes modes
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on some of those directories, and extracts a list of device entries to
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copy to a writable (again, a memory filesystem)
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<filename>/dev</filename> partition. In the execution of
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<filename>/etc/rc.diskless2</filename>, one other
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<filename>rc.conf</filename> variable comes into play -
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<literal>varsize</literal>. The <filename>/etc/rc.diskless2</filename>
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file creates a <filename>/var</filename> partition based on the value of
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this variable in <filename>rc.conf</filename>:</para>
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<programlisting>varsize=8192</programlisting>
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<para>Remember that this value is in sectors. The creation of the
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<filename>/dev</filename> partition by
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<filename>/etc/rc.diskless2</filename>, however, is governed by a
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hard-coded value of 4096 sectors. It is trivial to change this entry in
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the <filename>/etc/rc.diskless2</filename> file itself, although you
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should not need more space than that for
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<filename>/dev</filename>.</para>
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<para>It is important to remember that the
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<filename>/etc/rc.diskless2</filename> script assumes that you have
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already removed your conventional <filename>/tmp</filename> partition
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and replaced it with a symbolic link to <filename>/var/tmp</filename>.
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Because <filename>tmp</filename> is one of the directories created in
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<filename>/var</filename> by the <filename>/etc/rc.diskless2</filename>
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script, and because <filename>/var</filename> is a memory filesystem
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(which is mounted read-write), <filename>/tmp</filename> will now be a
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directory that is read-write as well.</para>
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<para>The fact that <filename>/var</filename> and
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<filename>/dev</filename> are read-write filesystems is an important
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distinction, as the <filename>/</filename> partition (and any other
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partitions you may have on your flash media) should be mounted
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read-only. Remember that in <xref linkend="intro"> we detailed the
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limitations of flash memory - specifically the limited write capability.
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The importance of not mounting filesystems on flash media read-write,
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and the importance of not using a swap file cannot be overstated. A
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swap file on a busy system can burn through a piece of flash media in
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less than one year. Heavy logging or temporary file creation and
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destruction can do the same. Therefore, in addition to removing the
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<literal>swap</literal> and <literal>/proc</literal> entries from your
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<filename>/etc/fstab</filename> file, you should also change the Options
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field for each filesystem to <literal>ro</literal> as follows:</para>
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<programlisting># Device Mountpoint FStype Options Dump Pass#
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/dev/ad0s1a / ufs ro 1 1</programlisting>
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<para>A few applications in the average system will immediately begin to
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fail as a result of this change. For instance, ports will not install
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from the ports tree because the
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<filename>/var/db/port.mkversion</filename> file does not exist. cron
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will not run properly as a result of missing cron tabs in the
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<filename>/var</filename> created by
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<filename>/etc/rc.diskless2</filename>, and syslog and dhcp will
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encounter problems as well as a result of the read-only filesystem and
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missing items in the <filename>/var</filename> that
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<filename>/etc/rc.diskless2</filename> has created. These are only
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temporary problems though, and are addressed, along with solutions to
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the execution of other common software packages in
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<xref linkend="strategies">.</para>
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<para>An important thing to remember is that a filesystem that was mounted
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read-only with <filename>/etc/fstab</filename> can be made read-write at
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any time by issuing the command:</para>
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<screen>&prompt.root; <userinput>/sbin/mount -uw <replaceable>partition</replaceable></userinput></screen>
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<para>and can be toggled back to read-only with the command:</para>
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<screen>&prompt.root; <userinput>/sbin/mount -ur <replaceable>partition</replaceable></userinput></screen>
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</sect1>
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<sect1>
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<title>Building a File System From Scratch</title>
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<para>Because ATA compatible compact-flash cards are seen by FreeBSD as
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normal IDE hard drives, as is a M-Systems Disk-On-Chip product (when you
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are running a kernel with the fla driver built in) you could
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theoretically install FreeBSD from the network using the kern and
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mfsroot floppies or from a CD. Other than the fact that you should not
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write a boot-loader of any kind to the M-Systems device, no special
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instructions are needed.</para>
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<para>However, even a small installation of FreeBSD using normal
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installation procedures can produce a system in size of greater than 200
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megabytes. Because most people will be using smaller flash memory
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devices (128 megabytes is considered fairly large - 32 or even 16
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megabytes is common) an installation using normal mechanisms is not
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possible—there is simply not enough disk space for even the
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smallest of conventional installations.</para>
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<para>The easiest way to overcome this space limitation is to install
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FreeBSD using conventional means to a normal hard disk. After the
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installation is complete, pare down the operating system to a size that
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will fit onto your flash media, then tar the entire filesystem. The
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following steps will guide you through the process of preparing a piece
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of flash memory for your tarred filesystem. Remember, because a normal
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installation is not being performed, operations such as partitioning,
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labeling, file-system creation, etc. need to be performed by hand. In
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addition to the kern and mfsroot floppy disks, you will also need to use
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the fixit floppy. If you are using a M-Systems Disk-On-Chip, the kernel
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on your kern floppy must have the <literal>fla</literal> option detailed
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in <xref linkend="kernel"> compiled into it. Please see
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<xref linkend="kern.flp"> for instructions on creating a new kernel for
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<filename>kern.flp</filename>.</para>
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<procedure>
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<step>
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<title>Partitioning your flash media device</title>
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<para>After booting with the kern and mfsroot floppies, choose
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<literal>custom</literal> from the installation menu. In the custom
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installation menu, choose <literal>partition</literal>. In the
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partition menu, you should delete all existing partitions using the
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<keycap>d</keycap> key. After deleting all existing partitions,
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create a partition using the <keycap>c</keycap> key and accept the
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default value for the size of the partition. When asked for the
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type of the partition, make sure the value is set to
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<literal>165</literal>. Now write this partition table to the disk
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by pressing the <keycap>w</keycap> key (this is a hidden option on
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this screen). When presented with a menu to choose a boot manager,
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take care to select <literal>None</literal> if you are using an
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M-Systems Disk-On-Chip. If you are using a ATA compatible compact
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flash card, you should choose the FreeBSD Boot Manager. Now press
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the <keycap>q</keycap> key to quit the partition menu. You will be
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shown the boot manager menu once more - repeat the choice you made
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earlier.</para>
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</step>
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<step>
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<title>Creating filesystems on your flash memory device</title>
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<para>Exit the custom installation menu, and from the main
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installation menu choose the <literal>fixit</literal> option. After
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entering the fixit environment, enter the following commands:</para>
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<informaltable frame="none">
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<tgroup cols="2">
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<thead>
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<row>
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<entry align="center">ATA compatible</entry>
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<entry align="center">Disk-On-Chip</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><para><screen>&prompt.root; <userinput>mknod /dev/ad0a c 116 0</userinput>
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&prompt.root; <userinput>mknod /dev/ad0c c 116 2</userinput>
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&prompt.root; <userinput>disklabel -e /dev/ad0c</userinput></screen></para></entry>
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<entry><para><screen>&prompt.root; <userinput>mknod /dev/fla0a c 102 0</userinput>
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&prompt.root; <userinput>mknod /dev/fla0c c 102 2</userinput>
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&prompt.root; <userinput>disklabel -e /dev/fla0c</userinput></screen></para></entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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<para>At this point you will have entered the vi editor under the
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auspices of the disklabel command. If you are using Disk-On-Chip,
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the first step will be to change the type value near the beginning
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of the file from <literal>ESDI</literal> to
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<literal>DOC2K</literal>. Next, regardless of whether you are using
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Disk-On-Chip or ATA compatible compact flash media, you need to add
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an a: line at the end of the file. This <literal>a:</literal> line
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should look like:</para>
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<programlisting>a: <replaceable>123456</replaceable> 0 4.2BSD 0 0</programlisting>
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<para>Where <replaceable>123456</replaceable> is a number that is
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exactly the same as the number in the existing <literal>c:</literal>
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entry for size. Basically you are duplicating the existing
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<literal>c:</literal> line as an <literal>a:</literal> line, making
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sure that fstype is <literal>4.2BSD</literal>. Save the file and
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exit.</para>
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<informaltable frame="none">
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<tgroup cols="2">
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<thead>
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<row>
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<entry align="center">ATA compatible</entry>
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<entry align="center">Disk-On-Chip</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><para><screen>&prompt.root; <userinput>disklabel -B -r /dev/ad0c</userinput>
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&prompt.root; <userinput>newfs /dev/ad0a</userinput></screen></para></entry>
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<entry><para><screen>&prompt.root; <userinput>disklabel -B -r /dev/fla0c</userinput>
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&prompt.root; <userinput>newfs /dev/fla0a</userinput></screen></para></entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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</step>
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<step>
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<title>Placing your filesystem on the flash media</title>
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<para>Mount the newly prepared flash media:</para>
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<informaltable frame="none">
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<tgroup cols="2">
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<thead>
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<row>
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<entry align="center">ATA compatible</entry>
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<entry align="center">Disk-On-Chip</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><para><screen>&prompt.root; <userinput>mount /dev/ad0a /flash</userinput></screen></para></entry>
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<entry><para><screen>&prompt.root; <userinput>mount /dev/fla0a /flash</userinput></screen></para></entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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<para>Bring this machine up on the network so we may transfer our tar
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file and explode it onto our flash media filesystem. One example of
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how to do this is:</para>
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<screen>&prompt.root; <userinput>ifconfig xl0 192.168.0.10 netmask 255.255.255.0</userinput>
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&prompt.root; <userinput>route add default 192.168.0.1</userinput></screen>
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<para>Now that the machine is on the network, transfer your tar file.
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You may be faced with a bit of a dilemma at this point - if your
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flash memory part is 128 megabytes, for instance, and your tar file
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is larger than 64 megabytes, you cannot have your tar file on the
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flash media at the same time as you explode it - you will run out of
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space. One solution to this problem, if you are using FTP, is to
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untar the file while it is transferred over FTP. If you perform
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your transfer in this manner, you will never have the tar file and
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the tar contents on your disk at the same time:</para>
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<screen><prompt>ftp></prompt> <userinput>get tarfile.tar "| tar xvf -"</userinput></screen>
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<para>If your tarfile is gzipped, you can accomplish this as
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well:</para>
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<screen><prompt>ftp></prompt> <userinput>get tarfile.tar "| zcat | tar xvf -"</userinput></screen>
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<para>After the contents of your tarred filesystem are on your flash
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memory filesystem, you can unmount the flash memory and
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reboot:</para>
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<screen>&prompt.root; <userinput>cd /</userinput>
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&prompt.root; <userinput>umount /flash</userinput>
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&prompt.root; <userinput>exit</userinput></screen>
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<para>Assuming that you configured your filesystem correctly when it
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was built on the normal hard disk (with your filesystems mounted
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read-only, and with the necessary options compiled into the kernel)
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you should now be successfully booting your FreeBSD embedded
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system.</para>
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</step>
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</procedure>
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</sect1>
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<sect1 id="kern.flp">
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<title>Building a <filename>kern.flp</filename> Installation Floppy with
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the fla Driver</title>
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|
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<note>
|
|
<para>This section of the article is relevant only to those using
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M-Systems Disk-On-Chip flash media.</para>
|
|
</note>
|
|
|
|
<para>It is possible that your <filename>kern.flp</filename> boot floppy
|
|
does not have a kernel with the <devicename>fla</devicename> driver
|
|
compiled into it necessary for the system to recognize the Disk-On-Chip.
|
|
If you have booted off of the installation floppies and are told that no
|
|
disks are present, then you are probably lacking the
|
|
<devicename>fla</devicename> driver in your kernel.</para>
|
|
|
|
<para>After you have built a kernel with <devicename>fla</devicename>
|
|
support that is smaller than 1.4 megabytes, you can create a custom
|
|
<filename>kern.flp</filename> floppy image with it by following these
|
|
instructions:</para>
|
|
|
|
<procedure>
|
|
<step>
|
|
<para>Obtain an existing kern.flp image file</para>
|
|
</step>
|
|
|
|
<step>
|
|
<para><screen>&prompt.root; <userinput>vnconfig vn0c kern.flp</userinput></screen></para>
|
|
</step>
|
|
|
|
<step>
|
|
<para><screen>&prompt.root; <userinput>mount /dev/vn0c /mnt</userinput></screen></para>
|
|
</step>
|
|
|
|
<step>
|
|
<para>Place your kernel file into <filename>/mnt</filename>, replacing
|
|
the existing one</para>
|
|
</step>
|
|
|
|
<step>
|
|
<para><screen>&prompt.root; <userinput>vnconfig -d vn0c</userinput></screen></para>
|
|
</step>
|
|
</procedure>
|
|
|
|
<para>Your <filename>kern.flp</filename> file now has your new kernel on it.</para>
|
|
</sect1>
|
|
|
|
<sect1 id="strategies">
|
|
<title>System Strategies for Small and Read Only Environments</title>
|
|
|
|
<para>In <xref linkend="ro-fs">, it was pointed out that the
|
|
<filename>/var</filename> filesystem constructed by
|
|
<filename>/etc/rc.diskless2</filename> and the presence of a read-only
|
|
root filesystem causes problems with many common software packages used
|
|
with FreeBSD. In this article, suggestions for successfully running
|
|
cron, syslog, ports installations, and the Apache web server will be
|
|
provided.</para>
|
|
|
|
<sect2>
|
|
<title>cron</title>
|
|
|
|
<para>In <filename>/etc/rc.diskless2</filename> there is a variable
|
|
named <literal>var_dirs</literal>. This variable consists of a
|
|
space-delimited list of directories that will be created inside of
|
|
<filename>/var</filename> after it is mounted as a memory filesystem.
|
|
<filename>cron</filename> and <filename>cron/tabs</filename> are not
|
|
in that list, and without those directories, cron will complain. By
|
|
inserting <literal>cron</literal>, <literal>cron/tabs</literal>, and
|
|
perhaps even <literal>at</literal>, and <literal>at/jobs</literal> as
|
|
elements of that variable, you will facilitate the running of the
|
|
&man.cron.8; and &man.at.1; daemons.</para>
|
|
|
|
<para>However, this still does not solve the problem of maintaining cron
|
|
tabs across reboots. When the system reboots, the
|
|
<filename>/var</filename> filesystem that is in memory will disappear
|
|
and any cron tabs you may have had in it will also disappear.
|
|
Therefore, one solution would be to create cron tabs for the users
|
|
that need them, mount your <filename>/</filename> filesystem as
|
|
read-write and copy those cron tabs to somewhere safe, like
|
|
<filename>/etc/tabs</filename>, then add a line to the end of
|
|
<filename>/etc/rc.diskless2</filename> that copies those crontabs into
|
|
<filename>/var/cron/tabs</filename> after that directory has been
|
|
created during system initialization. You may also need to add a line
|
|
that changes modes and permissions on the directories you create and
|
|
the files you copy with <filename>/etc/rc.diskless2</filename>.</para>
|
|
</sect2>
|
|
|
|
<sect2>
|
|
<title>syslog</title>
|
|
|
|
<para><filename>syslog.conf</filename> specifies the locations of
|
|
certain log files that exist in <filename>/var/log</filename>. These
|
|
files are not created by <filename>/etc/rc.diskless2</filename> upon
|
|
system initialization. Therefore, somewhere in
|
|
<filename>/etc/rc.diskless2</filename>, after the section that creates
|
|
the directories in <filename>/var</filename>, you will need to add
|
|
something like this:</para>
|
|
|
|
<screen>&prompt.root; <userinput>touch /var/log/security /var/log/maillog /var/log/cron /var/log/messages</userinput>
|
|
&prompt.root; <userinput>chmod 0644 /var/log/*</userinput></screen>
|
|
|
|
<para>You will also need to add the log directory to the list of
|
|
directories that <filename>/etc/rc.diskless2</filename>
|
|
creates.</para>
|
|
</sect2>
|
|
|
|
<sect2>
|
|
<title>ports installation</title>
|
|
|
|
<para>Before discussing the changes necessary to successfully use the
|
|
ports tree, a reminder is necessary regarding the read-only nature of
|
|
your filesystems on the flash media. Since they are read-only, you
|
|
will need to temporarily mount them read-write using the mount syntax
|
|
shown in <xref linkend="ro-fs">. You should always remount those
|
|
filesystems read-only when you are done with any maintenance - it is
|
|
dangerous to leave them in read-write mode lest a process begin
|
|
logging or otherwise writing regularly to the flash media and wearing
|
|
it out over time.</para>
|
|
|
|
<para>To make it possible to enter a ports directory and successfully
|
|
run <command>make install</command>, it is necessary for the file
|
|
<filename>/var/db/port.mkversion</filename> to exist, and that it have
|
|
a correct date in it. Further, we must create a packages directory on
|
|
a non-memory filesystem that will keep track of our packages across
|
|
reboots. Because it is necessary to mount your filesystems as
|
|
read-write for the installation of a package anyway, it is sensible to
|
|
assume that an area on the flash media can also be used for package
|
|
information to be written to.</para>
|
|
|
|
<para>First, create a package database directory. This is normally in
|
|
<filename>/var/db/pkg</filename>, but we cannot place it there as it
|
|
will disappear every time the system is booted.</para>
|
|
|
|
<screen>&prompt.root; <userinput>mkdir /etc/pkg</userinput></screen>
|
|
|
|
<para>Now, add a line to <filename>/etc/rc.diskless2</filename> that
|
|
links the <filename>/etc/pkg</filename> directory to
|
|
<filename>/var/db/pkg</filename>. An example:</para>
|
|
|
|
<screen>&prompt.root; <userinput>ln -s /etc/pkg /var/db/pkg</userinput></screen>
|
|
|
|
<para>Add another line in <filename>/etc/rc.diskless2</filename> that
|
|
creates and populates
|
|
<filename>/var/db/port.mkversion</filename></para>
|
|
|
|
<screen>&prompt.root; <userinput>touch /var/db/port.mkversion</userinput>
|
|
&prompt.root; <userinput>chmod 0644 /var/db/port.mkversion</userinput>
|
|
&prompt.root; <userinput>echo <replaceable>20010412</replaceable> >> /var/db/port.mkversion</userinput></screen>
|
|
|
|
<para>where <replaceable>20010412</replaceable> is a date that is
|
|
appropriate for your particular release of FreeBSD</para>
|
|
|
|
<para>Now, any time that you mount your filesystems as read-write and
|
|
install a package, the <command>make install</command> will work
|
|
because it finds a suitable
|
|
<filename>/var/db/port.mkversion</filename>, and package information
|
|
will be written successfully to <filename>/etc/pkg</filename> (because
|
|
the filesystem will, at that time, be mounted read-write) which will
|
|
always be available to the operating system as
|
|
<filename>/var/db/pkg</filename>.</para>
|
|
</sect2>
|
|
|
|
<sect2>
|
|
<title>Apache Web Server</title>
|
|
|
|
<para>Apache keeps pid files and logs in
|
|
<filename><replaceable>apache_install</replaceable>/logs</filename>.
|
|
Since this directory no doubt exists on a read-only filesystem, this
|
|
will not work. It is necessary to add a new directory to the
|
|
<filename>/etc/rc.diskless2</filename> list of directories to create
|
|
in <filename>/var</filename>, to link
|
|
<filename><replaceable>apache_install</replaceable>/logs</filename> to
|
|
<filename>/var/log/apache</filename>. It is also necessary to set
|
|
permissions and ownership on this new directory.</para>
|
|
|
|
<para>First, add the directory <literal>log/apache</literal> to the list
|
|
of directories to be created in
|
|
<filename>/etc/rc.diskless2</filename>.</para>
|
|
|
|
<para>Second, add these commands to
|
|
<filename>/etc/rc.diskless2</filename> after the directory creation
|
|
section:</para>
|
|
|
|
<screen>&prompt.root; <userinput>chmod 0774 /var/log/apache</userinput>
|
|
&prompt.root; <userinput>chown nobody:nobody /var/log/apache</userinput></screen>
|
|
|
|
<para>Finally, remove the existing
|
|
<filename><replaceable>apache_install</replaceable>/logs</filename>
|
|
directory, and replace it with a link:</para>
|
|
|
|
<screen>&prompt.root; <userinput>rm -rf (apache_install)/logs</userinput>
|
|
&prompt.root; <userinput>ln -s /var/log/apache (apache_install)/logs</userinput></screen>
|
|
</sect2>
|
|
</sect1>
|
|
</article>
|
|
|