ZFS disk replacement questions

Derrick Ryalls ryallsd at gmail.com
Tue Nov 3 19:32:41 UTC 2009

On Tue, Nov 3, 2009 at 10:21 AM, Steve Polyack <korvus at comcast.net> wrote:
> Derrick Ryalls wrote:
>> 1) In the event of a disk failure, how do I trace back the name such
>> as adX to a physical drive in the enclosure?  Is there a way to take
>> the drive offline then use atacontrol to spin it down or something so
>> it is easy to identify?
> In my opinion you are best off using glabel(8) to give names to the disks.
>  This way you can name them in a way that makes sense to you.  Additionally,
> when you create the ZFS pool you will use the glabel'd names.  This means
> that the pool will still come up properly if something causes your devices
> to be numbered differently (i.e. a drive dies and you happen to reboot the
> system).

I believe ZFS does this automatically.  Supposedly, if you take a
working set of RAIDZ drives from one machine and put it in another,
ZFS will figure out the drives since they get labelled by ZFS
internally.  My question concerns how to identify the physical disk in
question based on the adX or glabel name?  Different name in software
is fine, but if the drive fails I want to make sure I pull the correct

> Depending on your controller it is also probably worth it to use one of the
> SATA-specific drivers in FreeBSD 8 - these are ones like ahci(4) and
> siis(4).  While the generic ata(4) driver will work for pretty much
> everything, the updated AHCI drivers can take advantage of some more
> features.  Enable the modules at boot to use them.

I will look into it, thanks.  The machine in question is 2 year old
hardware currently with a 3ware raid card.  I will be going software
raid only, but FreeBSD already recognizes the eSATA drive I have
attached as a backup device so I know the O/S can at least talk to
sata drives attached to the mobo.

>> Any tips would be greatly appreciated.

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