From e4f3350c9fbc7e2a32161e75b41d6e8045ebcafa Mon Sep 17 00:00:00 2001 From: Dru Lavigne Date: Fri, 11 Apr 2014 15:47:38 +0000 Subject: [PATCH] Editorial review of Synopsis/Introduction and RAID0 sections. Sponsored by: iXsystems --- .../books/handbook/geom/chapter.xml | 135 ++++++++++-------- 1 file changed, 74 insertions(+), 61 deletions(-) diff --git a/en_US.ISO8859-1/books/handbook/geom/chapter.xml b/en_US.ISO8859-1/books/handbook/geom/chapter.xml index a91264c344..45ff6c3b65 100644 --- a/en_US.ISO8859-1/books/handbook/geom/chapter.xml +++ b/en_US.ISO8859-1/books/handbook/geom/chapter.xml @@ -26,31 +26,34 @@ Synopsis - GEOM + GEOM - GEOM Disk Framework - GEOM + GEOM Disk Framework + GEOM - This chapter covers the use of disks under the GEOM - framework in &os;. This includes the major RAID + In &os;, the GEOM framework permits access and control to classes, such as Master + Boot Records and BSD labels, through the use + of providers, or the disk devices in /dev. + By supporting various software RAID + configurations, GEOM transparently provides access to the + operating system and operating system utilities. + + This chapter covers the use of disks under the GEOM + framework in &os;. This includes the major RAID control utilities which use the framework for configuration. - This chapter will not go into in depth discussion on how GEOM - handles or controls I/O, the underlying subsystem, or code. - This information is provided in &man.geom.4; and its various - SEE ALSO references. This chapter is also + This chapter is not a definitive guide to RAID configurations - and only GEOM-supported RAID classifications - will be discussed. + and only GEOM-supported RAID classifications + are discussed. After reading this chapter, you will know: What type of RAID support is - available through GEOM. + available through GEOM. @@ -61,11 +64,11 @@ How to mirror, stripe, encrypt, and remotely connect - disk devices through GEOM. + disk devices through GEOM. - How to troubleshoot disks attached to the GEOM + How to troubleshoot disks attached to the GEOM framework. @@ -74,28 +77,17 @@ - Understand how &os; treats disk - devices. + Understand how &os; treats disk devices (). - Know how to configure and install a new - &os; kernel. + Know how to configure and install a new kernel + (. - - GEOM Introduction - - GEOM permits access and control to classes, such as Master - Boot Records and BSD labels, through the use - of providers, or the special files in /dev. - By supporting various software RAID - configurations, GEOM transparently provides access to the - operating system and operating system utilities. - - RAID0 - Striping @@ -119,30 +111,29 @@ - GEOM + GEOM Striping - Striping combine several disk drives into a single volume. - In many cases, this is done through the use of hardware - controllers. The GEOM disk subsystem provides software support - for RAID0, also known as disk - striping. + Striping combines several disk drives into a single volume. + Striping can be performed through the use of hardware + RAID controllers. The + GEOM disk subsystem provides software support + for disk striping, also known as RAID0, + without the need for a RAID disk + controller. - In a RAID0 system, data is split into - blocks that get written across all the drives in the array. - Instead of having to wait on the system to write 256k to one - disk, a RAID0 system can simultaneously write - 64k to each of four different disks, offering superior I/O + In RAID0, data is split into + blocks that are written across all the drives in the array. As + seen in the following illustration, + instead of having to wait on the system to write 256k to one + disk, RAID0 can simultaneously write + 64k to each of the four disks in the array, offering superior I/O performance. This performance can be enhanced further by using multiple disk controllers. - - Each disk in a RAID0 stripe must be of - the same size, since I/O requests are interleaved to read or - write to multiple disks in parallel. - + @@ -153,8 +144,26 @@ + Each disk in a RAID0 stripe must be of + the same size, since I/O requests are interleaved to read or + write to multiple disks in parallel. + + + RAID0 does not + provide any redundancy. This means that if one disk in the + array fails, all of the data on the disks is lost. If the + data is important, implement a backup strategy that regularly + saves backups to a remote system or device. + + + The process for creating a software, + GEOM-based RAID0 on a &os; + system using commodity disks is as follows. Once the stripe is + created, refer to &man.gstripe..8; for more information on how + to control an existing stripe. + - Creating a Stripe of Unformatted ATA Disks + Creating a Stripe of Unformatted <acronym>ATA</acronym> Disks Load the geom_stripe.ko @@ -167,9 +176,7 @@ Ensure that a suitable mount point exists. If this volume will become a root partition, then temporarily use another mount point such as - /mnt: - - &prompt.root; mkdir /mnt + /mnt. @@ -199,8 +206,8 @@ Done. /dev/stripe in addition to st0. Those include st0a and - st0c. At this point, a file system - may be created on st0a using + st0c. At this point, a UFS file system + can be created on st0a using newfs: &prompt.root; newfs -U /dev/stripe/st0a @@ -209,12 +216,14 @@ Done. few seconds, the process will be complete. The volume has been created and is ready to be mounted. - + To manually mount the created disk stripe: &prompt.root; mount /dev/stripe/st0a /mnt + + To mount this striped file system automatically during the boot process, place the volume information in /etc/fstab. In this example, a permanent @@ -224,19 +233,23 @@ Done. &prompt.root; mkdir /stripe &prompt.root; echo "/dev/stripe/st0a /stripe ufs rw 2 2" \ >> /etc/fstab + + The geom_stripe.ko module must also be automatically loaded during system initialization, by adding a line to /boot/loader.conf: &prompt.root; echo 'geom_stripe_load="YES"' >> /boot/loader.conf + + RAID1 - Mirroring - GEOM + GEOM Disk Mirroring @@ -856,7 +869,7 @@ mountroot> - GEOM + GEOM Software RAID Devices @@ -1193,7 +1206,7 @@ raid/r0 OPTIMAL ada0 (ACTIVE (ACTIVE)) - GEOM + GEOM RAID3 @@ -1325,9 +1338,9 @@ Done. - GEOM Gate Network Devices + <acronym>GEOM</acronym> Gate Network Devices - GEOM supports the remote use of devices, such as disks, + GEOM supports the remote use of devices, such as disks, CD-ROMs, and files through the use of the gate utilities. This is similar to NFS. @@ -1373,7 +1386,7 @@ ggate0 Labeling Disk Devices - GEOM + GEOM Disk Labels @@ -1579,10 +1592,10 @@ ufsid/486b6fc16926168e N/A ad4s1f - UFS Journaling Through GEOM + UFS Journaling Through <acronym>GEOM</acronym> - GEOM + GEOM Journaling