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From: "Eugene M. Zheganin" <emz@norma.perm.ru>
Subject: HAST, zfs and local mirroring
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Date: Tue, 31 May 2016 23:18:32 +0500
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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.