Hi. I wat to start using HAST, I have two nodes and a pair of disk on each node. So I want to use HASt in an environment where each HAST resource would be mirrored. What is the preferred approach if I want to use ZFS on an end-device to avoid exsessive fscking, and, in the same time, I want to have some redundancy on a block level ? I see two possibility: HAST on a zvol of a mirrored pool, and a ZFS on a hast. But recently I heard that nested zfs (like zfs on zvol) is clamed unsupported. Futhermore, I have zfs on a geli on a zvol, and this solution proved itself to be very affected to livelocking - when disk i/o on a such fs is above some treshold, system is locking, and the only way out is to reset it. Should I chose geom_mirror to provide a device for HAST and the build ZFS on it ? Thanks. Eugene.
On Tue, May 31, 2016 at 11:18 AM, Eugene M. Zheganin <emz at norma.perm.ru> wrote:> I wat to start using HAST, I have two nodes and a pair of disk on each > node. So I want to use HASt in an environment where each HAST resource > would be mirrored. What is the preferred approach if I want to use ZFS on > an end-device to avoid exsessive fscking, and, in the same time, I want to > have some redundancy on a block level ? I see two possibility: HAST on a > zvol of a mirrored pool, and a ZFS on a hast. But recently I heard that > nested zfs (like zfs on zvol) is clamed unsupported. Futhermore, I have zfs > on a geli on a zvol, and this solution proved itself to be very affected to > livelocking - when disk i/o on a such fs is above some treshold, system is > locking, and the only way out is to reset it. Should I chose geom_mirror to > provide a device for HAST and the build ZFS on it ? >?The generally recommend way to do this is to create a HAST resource out of 1 disk from each system, and then build the ZFS pool using the HAST resources as the "disks". That way, your ZFS pool is made up of 2 HAST devices in a mirror vdev. And each of the two HAST devices uses one disk from each server (total of four disks). ? -- Freddie Cash fjwcash at gmail.com
Hi. On 01.06.16 02:49, Freddie Cash wrote:> On Tue, May 31, 2016 at 11:18 AM, Eugene M. Zheganin > <emz at norma.perm.ru <mailto:emz at norma.perm.ru>>wrote: > > I wat to start using HAST, I have two nodes and a pair of disk on > each node. So I want to use HASt in an environment where each HAST > resource would be mirrored. What is the preferred approach if I > want to use ZFS on an end-device to avoid exsessive fscking, and, > in the same time, I want to have some redundancy on a block level > ? I see two possibility: HAST on a zvol of a mirrored pool, and a > ZFS on a hast. But recently I heard that nested zfs (like zfs on > zvol) is clamed unsupported. Futhermore, I have zfs on a geli on a > zvol, and this solution proved itself to be very affected to > livelocking - when disk i/o on a such fs is above some treshold, > system is locking, and the only way out is to reset it. Should I > chose geom_mirror to provide a device for HAST and the build ZFS > on it ? > > > ?The generally recommend way to do this is to create a HAST resource > out of 1 disk from each system, and then build the ZFS pool using the > HAST resources as the "disks". > > That way, your ZFS pool is made up of 2 HAST devices in a mirror vdev. > > And each of the two HAST devices uses one disk from each server (total > of four disks). > ? > > >But I don't need two HAST devices, I need one, but redundant on each server. Eugene.
On Tue, May 31, 2016 at 11:18:32PM +0500, Eugene M. Zheganin wrote:> Hi. > > I wat to start using HAST, I have two nodes and a pair of disk on each > node. So I want to use HASt in an environment where each HAST resource > would be mirrored. What is the preferred approach if I want to use ZFS > on an end-device to avoid exsessive fscking, and, in the same time, I > want to have some redundancy on a block level ? I see two possibility: > HAST on a zvol of a mirrored pool, and a ZFS on a hast. But recently I > heard that nested zfs (like zfs on zvol) is clamed unsupported. > Futhermore, I have zfs on a geli on a zvol, and this solution proved > itself to be very affected to livelocking - when disk i/o on a such fs > is above some treshold, system is locking, and the only way out is to > reset it. Should I chose geom_mirror to provide a device for HAST and > the build ZFS on it ?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.