zfs discuss - Apr 2007 - raidz pool with a slice on the boot disk

I created a pool with the following command?

zpool create -f batches raidz c0t0d0s7 c0t1d0 c0t2d0 c0t3d0

Notice that I specified slice 7, which is an unused slice on my boot disk t0. 
No part of the operating system exists on slice 7.  Is this acceptable? Will
this jeopardize the redundancy of my raidz pool with part of it on the boot
disk?
 
 
This message posted from opensolaris.org

Hi Russell,

Russell Baird wrote:
> I created a pool with the following command?
> 
> zpool create -f batches raidz c0t0d0s7 c0t1d0 c0t2d0 c0t3d0
> 
> Notice that I specified slice 7, which is an unused slice on my boot disk
> t0.  No part of the operating system exists on slice 7.  Is this
acceptable?
> Will this jeopardize the redundancy of my raidz pool with part of it on the
> boot disk?
no, this should work fine from a ZFS perspective. I''ve been running a
much more
complicated setup at home for over a year and it worked well.

That said, you still might want to reconsider: If your boot disk fails,
you''ll
need to replace it and repartition it to fit your raid scheme before you
can replace the s7 part of your RAID-Z. That might be a hassle you want to
avoid.

Out of a s similar situation, I decided to invest into more disks and
then host my data and my OS on separate disks. The goal is to keep everything
that makes your server unique (data + copies of any config changes etc.)
onto a separate pool that can easily be plugged into a different, plain vanilla
server, while leaving the boot filesystem as untouched as possible.

This is just a recommendation with the goal of reducing administration
and recovery complexity. As said, there should be no real harm from your
config.

There is a slight performance impact though: ZFS will enable the disk
write cache on c0t1-t3 but not on c0t0, so, effectively, c0t0 is going to
be the slowest drive in the RAID-Z set during certain circumstances and
therefore slightly affect the performance of the RAID-Z vdev.

Hope this helps,
   Constantin

-- 
Constantin Gonzalez                            Sun Microsystems GmbH, Germany
Platform Technology Group, Global Systems Engineering      http://www.sun.de/
Tel.: +49 89/4 60 08-25 91                   http://blogs.sun.com/constantin/

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