From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Peter Niemayer <niemayer@isg.de>
Cc: Eric Sandeen <sandeen@sandeen.net>, xfs@oss.sgi.com
Subject: Re: XFS support for TRIM / blkdev_issue_discard?
Date: Mon, 20 Apr 2009 15:11:19 -0400 [thread overview]
Message-ID: <yq1ab6b2l9k.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <49ECC2CA.20108@isg.de> (Peter Niemayer's message of "Mon, 20 Apr 2009 20:45:30 +0200")
>>>>> "Peter" == Peter Niemayer <niemayer@isg.de> writes:
Peter> And I did not find any requirement or hint to "tell the largest
Peter> free space around the area just freed" in
Peter> http://www.t13.org/Documents/UploadedDocuments/docs2008/e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
This was never an issue with SSDs. The requirement comes from
thin-provisioned SCSI disk arrays that would like us to do unmaps
(trims) in units of their internal block size.
There was a huge pushback from the industry about this. This is clearly
something the array firmware should have to keep track of and not the
operating system. As a result the unmap granularity size proposal was
pulled and for a while it looked like everything was going to be fine.
Unfortunately yet another array vendor recently discovered that thin
provisioning is hard and sent out a request to have the granularity
brain damage reinstated in the latest protocol draft.
I'm just hoping that all the vendors who came around on the issue will
stay that way...
--
Martin K. Petersen Oracle Linux Engineering
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prev parent reply other threads:[~2009-04-20 19:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-31 5:30 [GIT PULL] XFS update for 2.6.30 Felix Blyakher
2009-04-02 16:26 ` Felix Blyakher
2009-04-03 16:52 ` Linus Torvalds
2009-04-03 17:02 ` Linus Torvalds
2009-04-03 17:41 ` Felix Blyakher
2009-04-04 1:19 ` david
2009-04-04 1:54 ` Felix Blyakher
2009-04-14 14:44 ` XFS support for TRIM / blkdev_issue_discard? Peter Niemayer
2009-04-14 18:32 ` Felix Blyakher
2009-04-15 9:43 ` Peter Niemayer
2009-04-15 11:58 ` Peter Niemayer
2009-04-17 16:09 ` Peter Niemayer
2009-04-17 16:50 ` Eric Sandeen
2009-04-19 8:19 ` Dave Chinner
2009-04-19 15:51 ` Eric Sandeen
2009-04-20 18:45 ` Peter Niemayer
2009-04-20 19:11 ` Martin K. Petersen [this message]
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