FITRIM/discard - Revision history

J3gum: /* References */

2012-08-31T16:25:33Z

References

← Older revision		Revision as of 16:25, 31 August 2012
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	== References ==		== References ==
	# FITRIM description - Lukas Czerner <lczerner at redhat.com> http://patchwork.xfs.org/patch/1490/		# FITRIM description - Lukas Czerner <lczerner at redhat.com> 2010-12-10 15:53:27 Message ID <1291996407-26251-1-git-send-email-lczerner@redhat.com> http://patchwork.xfs.org/patch/1490/
	# Block requirements - Dave Chinner <david at fromorbit.com> http://oss.sgi.com/pipermail/xfs/2011-October/~~053379~~.html		# Block requirements - Dave Chinner <david at fromorbit.com> 2011-10-10 21:05:52 http://oss.sgi.com/pipermail/xfs/2011-October/014867.html
	# util-linux-ng addition - Karel Zak <kzak@xxxxxxxxxx> http://www.spinics.net/lists/util-linux-ng/msg03646.		# util-linux-ng addition - Karel Zak <kzak@xxxxxxxxxx> 2010-11-26 15:17:39 http://www.spinics.net/lists/util-linux-ng/msg03646.html
	# Online TRIM/discard performance impact - http://oss.sgi.com/pipermail/xfs/2011-November/~~053841~~.html		# Online TRIM/discard performance impact - Christoph Hellwig <hch at infradead.org> 2011-11-07 04:21:21 http://oss.sgi.com/pipermail/xfs/2011-November/015329.html

Ckujau: SPAM: Undo revision 2433 by Vegasseo (Talk)

2012-03-17T03:23:54Z

SPAM: Undo revision 2433 by Vegasseo (Talk)

← Older revision		Revision as of 03:23, 17 March 2012
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	== Purpose ==		== Purpose ==

	FITRIM is a mounted filesystem feature to discard (or "[~~http~~://en.wikipedia.org/wiki/TRIM trim]") blocks which are not in use by the filesystem. This is useful for solid-state drives (SSDs) and thinly-provisioned storage.		FITRIM is a mounted filesystem feature to discard (or "[https://en.wikipedia.org/wiki/TRIM trim]") blocks which are not in use by the filesystem. This is useful for solid-state drives (SSDs) and thinly-provisioned storage.

	== Requirements ==		== Requirements ==
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	=== Batch Mode ===		=== Batch Mode ===

	This mode requires user intervention. This intervention is in the form of the command <code>fstrim</code>. It has been included in [~~http~~://en.wikipedia.org/wiki/Util-linux util-linux-ng] ~~[http://www.bobsseo.com~~ since] about Nov 26, 2010.		This mode requires user intervention. This intervention is in the form of the command <code>fstrim</code>. It has been included in [https://en.wikipedia.org/wiki/Util-linux util-linux-ng] since about Nov 26, 2010.

	Usage example:		Usage example:

Vegasseo: /* Batch Mode */

2012-03-17T03:14:13Z

Batch Mode

← Older revision		Revision as of 03:14, 17 March 2012
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	=== Batch Mode ===		=== Batch Mode ===

	This mode requires user intervention. This intervention is in the form of the command <code>fstrim</code>. It has been included in [http://en.wikipedia.org/wiki/Util-linux util-linux-ng] since about Nov 26, 2010.		This mode requires user intervention. This intervention is in the form of the command <code>fstrim</code>. It has been included in [http://en.wikipedia.org/wiki/Util-linux util-linux-ng] [http://www.bobsseo.com since] about Nov 26, 2010.

	Usage example:		Usage example:

J3gum: Added performance issues for realtime discard.

2011-11-07T15:54:47Z

Added performance issues for realtime discard.

← Older revision		Revision as of 15:54, 7 November 2011
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	This mode issues discard requests automatically as files are removed from the filesystem. No other command or process is required.		This mode issues discard requests automatically as files are removed from the filesystem. No other command or process is required.

			There can be a severe performance penalty for enabling realtime discard. (4)

	Realtime discard is selected by adding the filesystem option <code>discard</code> while mounting.		Realtime discard is selected by adding the filesystem option <code>discard</code> while mounting.
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	# FITRIM description - Lukas Czerner <lczerner at redhat.com> http://patchwork.xfs.org/patch/1490/		# FITRIM description - Lukas Czerner <lczerner at redhat.com> http://patchwork.xfs.org/patch/1490/
	# Block requirements - Dave Chinner <david at fromorbit.com> http://oss.sgi.com/pipermail/xfs/2011-October/053379.html		# Block requirements - Dave Chinner <david at fromorbit.com> http://oss.sgi.com/pipermail/xfs/2011-October/053379.html
	# util-linux-ng addition - Karel Zak <kzak@xxxxxxxxxx> http://www.spinics.net/lists/util-linux-ng/msg03646.html		# util-linux-ng addition - Karel Zak <kzak@xxxxxxxxxx> http://www.spinics.net/lists/util-linux-ng/msg03646.
			# Online TRIM/discard performance impact - http://oss.sgi.com/pipermail/xfs/2011-November/053841.html

Dgc at 22:30, 11 October 2011

2011-10-11T22:30:46Z

← Older revision		Revision as of 22:30, 11 October 2011
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	#The block device underneath the filesystem must support the FITRIM operation.		#The block device underneath the filesystem must support the FITRIM operation.
	#The kernel must include TRIM support and XFS must include FITRIM support (this has been true for Linux since v2.6.38, Jan 18 2011)		#The kernel must include TRIM support and XFS must include FITRIM support (this has been true for Linux since v2.6.38, Jan 18 2011)
			#Realtime discard mode requires a more recent v3.0 kernel

	This can be verified by viewing /sys/block/<dev>/queue/discard_max_bytes -- If the value is zero then your device doesn't support discard		This can be verified by viewing /sys/block/<dev>/queue/discard_max_bytes -- If the value is zero then your device doesn't support discard

J3gum: Initial creation

2011-10-11T16:03:00Z

Initial creation

New page

== Purpose ==

FITRIM is a mounted filesystem feature to discard (or "[http://en.wikipedia.org/wiki/TRIM trim]") blocks which are not in use by the filesystem. This is useful for solid-state drives (SSDs) and thinly-provisioned storage.

== Requirements ==

#The block device underneath the filesystem must support the FITRIM operation.
#The kernel must include TRIM support and XFS must include FITRIM support (this has been true for Linux since v2.6.38, Jan 18 2011)

This can be verified by viewing /sys/block/<dev>/queue/discard_max_bytes -- If the value is zero then your device doesn't support discard
operations.

== Modes of Operation ==

* Realtime discard -- As files are removed, the filesystem issues discard requests automatically
* Batch Mode -- A user procedure that trims all or portions of the filesystem

=== Realtime discard ===

This mode issues discard requests automatically as files are removed from the filesystem. No other command or process is required.

Realtime discard is selected by adding the filesystem option <code>discard</code> while mounting.

This can be done by the following examples:

# placing <code>discard</code> in your /etc/fstab for the filesystem: <code>/dev/sda1 /mountpoint xfs defaults,discard 0 1</code>
# mount options: <code>mount -o discard /dev/sda1 /mountpoint</code>

=== Batch Mode ===

This mode requires user intervention. This intervention is in the form of the command <code>fstrim</code>. It has been included in [http://en.wikipedia.org/wiki/Util-linux util-linux-ng] since about Nov 26, 2010.

Usage example:
<code>fstrim /mountpoint</code>

----

== References ==
# FITRIM description - Lukas Czerner <lczerner at redhat.com> http://patchwork.xfs.org/patch/1490/
# Block requirements - Dave Chinner <david at fromorbit.com> http://oss.sgi.com/pipermail/xfs/2011-October/053379.html
# util-linux-ng addition - Karel Zak <kzak@xxxxxxxxxx> http://www.spinics.net/lists/util-linux-ng/msg03646.html