Hello, I''ll use a complete SSD in a domU. How can I get the real device for TRIM into domU? Regards, Stefan Kuhne _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
Hello. El 24/10/12 12:18, Stefan Kuhne escribió:> I''ll use a complete SSD in a domU. > How can I get the real device for TRIM into domU?Apparently, TRIM command can naturally (and successfully) travel thorugh all the involved layers form DomU to the hardware, at least in case of PV Linux and LVM based storage. There was a more or less recent thread in this list that might help: http://lists.xen.org/archives/html/xen-users/2012-07/msg00088.html -- Alexandre Kouznetsov
Actually, there was an exchange with James Harper where he confirmed Windows GPLPV drivers did not yet have TRIM support, but I do not know whether using LVM underneath was related. He did say he was looking it add it to a future release, but I do not know if that release is available yet. Honestly, given how well the SSD I am using performs it doesn''t really matter much to me, but if you absolutely need it and are planning you pass the whole drive, you might consider IOMMU and passing the SATA Controller. I do not know if that will work, but if it has direct access to the SATA controller then it should support TRIM. On Wed, Oct 24, 2012 at 2:19 PM, Alexandre Kouznetsov <alk@ondore.com>wrote:> Hello. > > El 24/10/12 12:18, Stefan Kuhne escribió: > > I''ll use a complete SSD in a domU. >> How can I get the real device for TRIM into domU? >> > > Apparently, TRIM command can naturally (and successfully) travel thorugh > all the involved layers form DomU to the hardware, at least in case of PV > Linux and LVM based storage. > > There was a more or less recent thread in this list that might help: > http://lists.xen.org/archives/**html/xen-users/2012-07/**msg00088.html<http://lists.xen.org/archives/html/xen-users/2012-07/msg00088.html> > > -- > Alexandre Kouznetsov > > > ______________________________**_________________ > Xen-users mailing list > Xen-users@lists.xen.org > http://lists.xen.org/xen-users >_______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
> > Actually, there was an exchange with James Harper where he confirmed > Windows GPLPV drivers did not yet have TRIM support, but I do not know > whether using LVM underneath was related. He did say he was looking it > add it to a future release, but I do not know if that release is available yet. >Windows <= 7/2008R2 supports TRIM on AHCI (SATA) devices, but not the SCSI equivalent UNMAP for SCSI controllers. GPLPV''s xenvbd driver is based on storport which is SCSI as far as Windows is concerned. It appears that there could be a way with a Windows filter driver to turn higher level IOCTL''s into SCSI TRIM commands which could allow TRIM on <= 7/2008R2 but I don''t really have a lot of time to develop yet another driver. Windows 8/2012 does appear to support UNMAP, it certainly appears to query the VPD''s that would allow it to detect a thin provisioned device which is encouraging. This wouldn''t be too much work to implement, but I don''t have any SSD''s to test on at this time. James