[PC-BSD Testing] boot volume mirror maintenance

Kris Moore kris at pcbsd.org
Mon Aug 13 11:56:58 PDT 2012

On 08/13/2012 14:45, Dewey Hylton wrote:
>> From: "Kris Moore" <kris at pcbsd.org>
>> To: testing at lists.pcbsd.org
>> Sent: Monday, August 13, 2012 2:39:51 PM
>> Subject: Re: [PC-BSD Testing] boot volume mirror maintenance
>> On 08/13/2012 13:51, Dewey Hylton wrote:
>>> the pc-bsd installer provides a couple of mirrored boot volume
>>> options; i believe this is a huge win. devices do fail, however,
>>> and while having your box stay running is a definite plus, one
>>> should immediately replace the failed device and re-instate the
>>> mirror. i consider this standard maintenance.
>>> adding a mirror device to a zpool is simple, but i'm not sure about
>>> the multiple partition types (gpt/mbr) and the boot code itself.
>>> having the required steps handy for recovering from these
>>> scenarios is necessary for sysadmins - and i'm sure most end-users
>>> would prefer to not be forced to reinstall when storage is so
>>> cheap and mirroring can be this simple.
>>> i'd like to see documentation that shows exactly how to do these
>>> things. is this already available somewhere, or will i need to dig
>>> into the installer source to figure it out myself?
>>> _______________________________________________
>>> Testing mailing list
>>> Testing at lists.pcbsd.org
>>> http://lists.pcbsd.org/mailman/listinfo/testing
>> Luckily we keep a record of the process used to format the original
>> disks. Post-install if you look at /root/pc-sysinstall.log, you can
>> see
>> the actual commands used to create the initial disk setup. I've used
>> this here, to manually add a drive into a pool, with the exact same
>> disk
>> layout, etc.
>> --
>> Kris Moore
>> PC-BSD Software
>> iXsystems
> we need to have these scenarios documented somewhere. otherwise, it'd
> be difficult to mirror the boot volume after installation. for example
> i'm getting ready to perform another installation on a machine for
> which i do not yet have a secondary disk. that's what prompted me to
> look for the documentation in the first place, but much more important
> is the scenario where you would be replacing a failed drive. but of 
> course in my scenario i won't have the steps to follow from the log file.
Well, that log file exists after each install. So in your first case,
you can refer to it to see how the single disk layout was done, and
duplicate the commands before inserting it into the ZFS mirror. Ditto
for a replacement. But we will need to document this, so the user knows
that the file contains everything they need, command-wise, to re-create
the disk layout.

Kris Moore
PC-BSD Software

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