- Add Q2 entry on ZFS TRIM

Submitted by:	smh
This commit is contained in:
Gabor Pali 2013-07-03 07:15:29 +00:00
parent d59b977a8b
commit 39619deab7
Notes: svn2git 2020-12-08 03:00:23 +00:00
svn path=/head/; revision=42125

View file

@ -18,7 +18,7 @@
<!-- XXX: keep updating the number of entries -->
<p>Thanks to all the reporters for the excellent work! This report
contains 11 entries and we hope you enjoy reading it.</p>
contains 12 entries and we hope you enjoy reading it.</p>
<!-- XXX: set date for the next set of submissions -->
<p>The deadline for submissions covering between July and September 2013
@ -548,4 +548,62 @@
yet supported.</p>
</body>
</project>
<project cat='kern'>
<title>ZFS TRIM and Enhanced <tt>BIO_DELETE</tt> Support</title>
<contact>
<person>
<name>
<given>Pawel Jakub</given>
<common>Dawidek</common>
</name>
<email>pjd@FreeBSD.org</email>
</person>
<person>
<name>
<given>Steven</given>
<common>Hartland</common>
</name>
<email>smh@FreeBSD.org</email>
</person>
</contact>
<body>
<p>As of the end of June, &os;'s ZFS implementation now includes
TRIM support in <tt>head</tt>, <tt>stable/9</tt>, and
<tt>stable/8</tt> branches. This allows ZFS to help maintain
high performance on flash-based devices such as SSD's even under
high-load conditions.</p>
<p>When creating new pools and adding new devices to existing
pools it first performs a full-device level TRIM to help ensure
optimum starting performance. This behaviour can be overridden
by setting the <tt>vfs.zfs.vdev.trim_on_init</tt> sysctl
variable to <tt>0</tt> if for example the disks are new or have
already been secure erased, which can also now be done using
<tt>camcontrol(8)</tt> security actions.</p>
<p>In order to support TRIM, the kernel requires the underlying
device driver supports <tt>BIO_DELETE</tt>. This is currently
mapped through to hardware methods such as ATA TRIM and SCSI
UNMAP, which are commonly supported by SSDs via CAM.</p>
<p>In order to increase the supported hardware base, CAM's SCSI
layer was also enhanced to allow ATA TRIM via SATL ATA
Passthrough to be used in addition to the existing UNMAP and WS
methods. This allows SATA disks attached to SCSI controllers
with CAM based drivers such as <tt>mps(4)</tt> and
<tt>mpt(4)</tt> to provide delete support.</p>
<p>Stats for ZFS TRIM can be monitored by looking at the sysctl
variables under <tt>kstat.zfs.misc.zio_trim</tt> in addition to
live GEOM delete stats via the <tt>gstat -d</tt> command.</p>
<p>This project was sponsored by <a
href="http://www.multiplay.com">Multiplay</a> and implemented by
Pawel Jakub Dawidek.</p>
</body>
</project>
</report>