svn commit: r42125 - head/en_US.ISO8859-1/htdocs/news/status
Gabor Pali
pgj at FreeBSD.org
Wed Jul 3 07:15:30 UTC 2013
Author: pgj
Date: Wed Jul 3 07:15:29 2013
New Revision: 42125
URL: http://svnweb.freebsd.org/changeset/doc/42125
Log:
- Add Q2 entry on ZFS TRIM
Submitted by: smh
Modified:
head/en_US.ISO8859-1/htdocs/news/status/report-2013-04-2013-06.xml
Modified: head/en_US.ISO8859-1/htdocs/news/status/report-2013-04-2013-06.xml
==============================================================================
--- head/en_US.ISO8859-1/htdocs/news/status/report-2013-04-2013-06.xml Wed Jul 3 07:02:33 2013 (r42124)
+++ head/en_US.ISO8859-1/htdocs/news/status/report-2013-04-2013-06.xml Wed Jul 3 07:15:29 2013 (r42125)
@@ -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 at FreeBSD.org</email>
+ </person>
+
+ <person>
+ <name>
+ <given>Steven</given>
+ <common>Hartland</common>
+ </name>
+ <email>smh at 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>
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