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Date: Sat, 13 Apr 2013 19:53:18 +0200
From: Adam Nowacki <nowakpl@platinum.linux.pl>
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To: freebsd-fs@freebsd.org
Subject: Re: ZFS: ZIL device export/import
References: <5A2824CA-2A67-47FA-AB27-20C6EBD2C501@alumni.chalmers.se>
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On 2013-04-13 19:33, mxb wrote:
>
> Hello list,
>
> I'm currently have 2x Head Units (HU) [FreeBSD 9.1] connected to the same JBOD via SAS Expander.
> Each HU has separate ZIL and L2ARC devices. Hardware on both HU (inc. SSD disks for ZIL/L2ARC) is identical.
>
> This is basically a HA-setup.
>
> The I do an 'zpool export tank' on the first HU and do 'zpool import tank' on the second one, only L2ARC device appears usable.
> Import fails, complaining about ZIL device not present.
>
> According to the man page zpool(8) ZIL device can be imported and exported.
>
> "… Log devices can be added, replaced, attached, detached, imported and
>       exported as part of the larger pool. …".
>
> Do I miss something here?
> This feature not implemented yet?
> Any way to work around this, except that moving ZIL into JBOD?

 From the same man page:
-m      Enables import with missing log devices.

... but that won't be HA since on unclean shutdown of one the other 
won't be able to replay the log and some recent writes (or worse) will 
be lost.