Hi, I found one post at the qemu-devel list regarding this feature, see:
http://www.archivum.info/[email protected]/2009-03/00220/% 28Qemu-devel% 29-Using-the-ATA-quot-trim-quot-command-to-discard-sectors-in-disk-images.html I couldn't find any more posts then this one, so no idea when it will be implemented in Qemu. -- Met vriendelijke groet, Wido den Hollander Hoofd Systeembeheer / CSO Telefoon Support Nederland: 0900 9633 (45 cpm) Telefoon Support België: 0900 70312 (45 cpm) Telefoon Direct: (+31) (0)20 50 60 104 Fax: +31 (0)20 50 60 111 E-mail: [email protected] Website: http://www.pcextreme.nl Kennisbank: http://support.pcextreme.nl/ Netwerkstatus: http://nmc.pcextreme.nl On Tue, 2010-04-13 at 02:27 +0000, FUJITA Tomonori wrote: > On Mon, 12 Apr 2010 12:46:49 +0200 > Wido den Hollander <[email protected]> wrote: > > > Since kernel version 2.6.33 Linux supports the "discard" commando, > > mainly used by SSD's for their wear-leveling and performance. > > > > It's also called TRIM: http://en.wikipedia.org/wiki/TRIM > > > > At the moment only Btrfs and EXT4 support trim/discard, but this could > > be a nice feature for sheepdog. > > > > If sheepdog reads the "discard" messages from the kernel in the VM you > > could figure out which blocks are free again and shrink the used space > > automatically. > > Yeah, I saw Christoph's demonstration that the guest kernel issues a > trim command then qemu's image shrinks on the host. We could do > similar. > > The version of qemu that we use now for Sheepdog doesn't notify the > block drivers when the host kernel issues a trim command (or SCSI > equivalents). I'm not sure about the latest version. But when qemu is > ready, then we would work on sheepdog about this feature. -- sheepdog mailing list [email protected] http://lists.wpkg.org/mailman/listinfo/sheepdog
