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Subject: Re: HAST, zfs and local mirroring
To: stable@freebsd.org
References: <bf4a004f-8c7f-1e2e-0c31-3de266975ae4@norma.perm.ru>
 <20160601132300.GA75625@zxy.spb.ru>
From: "Eugene M. Zheganin" <emz@norma.perm.ru>
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Date: Thu, 2 Jun 2016 12:12:35 +0500
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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.