Hi. On 01.06.16 18:23, Slawa Olhovchenkov wrote:> > Only FS support changed data bypass FS layer is Files-11 ODS-2 level, > may be hardware support required. > > Can you use ZFS mirror with one vdev local and other vdev by iSCSI? > Every node using separate ZFS pool in this case.If you mean that I should distribute the HAST one-disk device via iSCSI and then use it as a half of zfs mirrored pool on each node, then I should ask how the pool will decide which half is more recent - local or iSCSI, after I will import it and the kernel will found that it's vdevs differs a lot ? And why should I prefere this overcomplicated scheme over the geom_mirror, which seems rather simple when comparing. Seems like I can point HAST to /dev/mirror/whatever device, right ? Thanks. Eugene.
On Thu, Jun 02, 2016 at 12:12:35PM +0500, Eugene M. Zheganin wrote:> Hi. > > On 01.06.16 18:23, Slawa Olhovchenkov wrote: > > > > Only FS support changed data bypass FS layer is Files-11 ODS-2 level, > > may be hardware support required. > > > > Can you use ZFS mirror with one vdev local and other vdev by iSCSI? > > Every node using separate ZFS pool in this case. > If you mean that I should distribute the HAST one-disk device via iSCSI > and then use it as a half of zfs mirrored pool on each node, then I > should ask how the pool will decide which half is more recent - local or > iSCSI, after I will import it and the kernel will found that it's vdevs > differs a lot ? And why should I prefere this overcomplicated scheme > over the geom_mirror, which seems rather simple when comparing. Seems > like I can point HAST to /dev/mirror/whatever device, right ?I am suggesting next setup: node0: own pool zroot0: mirror-0: local_disk0 remote-iscsi_disk1/1 local_disk1: exported by iscsi as remote-iscsi_disk0/1 to node1 node1: own pool zroot1: mirror-0: local_disk0 remote-iscsi_disk0/1 local_disk1: exported by iscsi as remote-iscsi_disk1/1 to node0 No HAST. Disks synced by ZFS over iSCSI.
On 2016-Jun-02 12:12:35 +0500, "Eugene M. Zheganin" <emz at norma.perm.ru> wrote:>differs a lot ? And why should I prefere this overcomplicated scheme >over the geom_mirror, which seems rather simple when comparing. Seems >like I can point HAST to /dev/mirror/whatever device, right ?Because using RAID of any sort under ZFS defeats a lot of the smarts in ZFS. In particular, you can no longer rely on scrub verifying that all your media content is valid. I've also had bad experiences with gmirror volumes silently getting out of sync on a crash. -- Peter Jeremy -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 949 bytes Desc: not available URL: <http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20160603/a2614984/attachment.sig>