From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ric Wheeler Subject: Re: TRIM vs UNMAP vs WRITE SAME and thin devices Date: Sun, 08 Feb 2009 19:01:23 -0500 Message-ID: <498F7253.1070002@redhat.com> References: <20090123041558.GC24652@parisc-linux.org> <4979AF62.7070409@redhat.com> <1232721777.4430.7.camel@macbook.infradead.org> <498DA052.6090605@redhat.com> <87f94c370902081206v71106c5fp9a7ef0400301a1ab@mail.gmail.com> <20090208204434.GF31509@parisc-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Greg Freemyer , David Woodhouse , James Bottomley , "Martin K. Petersen" , Jeff Garzik , linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, IDE/ATA development list To: Matthew Wilcox Return-path: In-Reply-To: <20090208204434.GF31509@parisc-linux.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Matthew Wilcox wrote: > On Sun, Feb 08, 2009 at 03:06:44PM -0500, Greg Freemyer wrote: > >> I found a list of T10 activities just since just Dec. 1, 2008 and it >> is a bit overwhelming. (ie. 08-356r4 is but one of many recent >> reports) >> >> http://www.t10.org/new_a.htm >> >> For those of us that don't live and breath the SCSI spec, is there an >> overview site describing what is going on. >> > > I've been working off 08-149r7.pdf. I'm sure that's been superseded by > now. > > >> 08-356r4 SBC-3: WRITE SAME unmap bit David L. Black PDF (56608) 2008/12/10 >> > > Probably interesting. Haven't read it myself. > This is only a four page proposal - basically, we would use the write same command with a special unmap bit set to tell the target that it may (at its option) unmap the blocks. If not, it would in fact have to set the data to the indicated pattern in the command which I presume would be all zeros in the normal case. > >> 08-356r5 SBC-3 Thin Provisioning Commands Fred Knight, David L. >> Black PDF (387549) 2009/01/15 >> > > Fred Knight seems to be the main coordinator of this effort, so yes. > Fred and David Black both have been quite active. > >> 08-149r7 SBC - Thin Provisioning Frederick Knight PDF (281001) 2008/12/08 >> > > That's the one I'm working from. > > >> 08-149r8 SBC - Thin Provisioning Frederick Knight PDF (281387) 2009/01/09 >> > > A newer version ... thought so. > > >> 09-011r1 SBC-3 Thin Provisioning Threshold Notification Frederick >> Knight PDF (32757) 2009/01/09 >> > > Clearly related. > > >> 08-149r9 SBC - Thin Provisioning Frederick Knight PDF (353888) 2009/01/15 >> > > Even newer version of what I've been working from. > > >> 09-012r0 Minutes: CAP - Thin Provisioning 12/4 con-call Frederick >> Knight PDF (38063) 2008/12/08 >> > > Probably tedious. > > >> 08-396r3 SPC-4: Reporting support for all DIF types George Penokie >> PDF (85358) 2009/01/14 >> > > Unrelated, I would think. > > I'd go with 08-149r9 to get a good overview. > >