HAST, zfs and local mirroring

[Eugene M. Zheganin]

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.