freebsd stable - Jun 2013 - ZFS LZ4 Upgrade

Hi. I'm planning on doing a ZFS root installation on a remote server very
soon. The company only offers a 9.0 and 9.1 installation and "rescue"
(nfs/pxe boot with ramdisk basically) system. I'd like to use LZ4 with the
ZFS root pool, so I'm going to be upgrading to -STABLE once I have the
initial system installed. Here's what I'll do:

- install the 9.1 system
- svn source, buildworld/kernel, install, reboot
- upon booting the -STABLE system, begin enabling LZ4 compression on /usr/ports
/usr/src etc.

Will this work, or do I need to find some way to initially create the zpool with
a -STABLE system? Is it just a matter of running "zfs upgrade" and
"zpool upgrade" before enabling LZ4, or am I missing something? Thanks

-kenta

On Jun 3, 2013, at 12:52 PM, Kenta Suzumoto <kentas at hush.com> wrote:
> Hi. I'm planning on doing a ZFS root installation on a remote server
very soon. The company only offers a 9.0 and 9.1 installation and
"rescue" (nfs/pxe boot with ramdisk basically) system. I'd like to
use LZ4 with the ZFS root pool, so I'm going to be upgrading to -STABLE once
I have the initial system installed. Here's what I'll do:
> 
> - install the 9.1 system
> - svn source, buildworld/kernel, install, reboot
> - upon booting the -STABLE system, begin enabling LZ4 compression on
/usr/ports /usr/src etc.
> 
> Will this work, or do I need to find some way to initially create the zpool
with a -STABLE system? Is it just a matter of running "zfs upgrade"
and "zpool upgrade" before enabling LZ4, or am I missing something?
Thanks
That should work. Just keep in mind that blocks written before you enable
compression won't be compressed. So you may want to create a _new_ ZFS for
src (and ports if it already exists as well) after your source upgrade, then
copy the contents of /usr/src over to it. (Then update the mountpoints as
desired, etc.)

JN

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On 06/03/13 11:52, Kenta Suzumoto wrote:
> Hi. I'm planning on doing a ZFS root installation on a remote
> server very soon. The company only offers a 9.0 and 9.1
> installation and "rescue" (nfs/pxe boot with ramdisk basically)
> system. I'd like to use LZ4 with the ZFS root pool, so I'm going to
> be upgrading to -STABLE once I have the initial system installed.
> Here's what I'll do:
> 
> - install the 9.1 system - svn source, buildworld/kernel, install, 
> reboot - upon booting the -STABLE system, begin enabling LZ4 
> compression on /usr/ports /usr/src etc.
> 
> Will this work, or do I need to find some way to initially create
> the zpool with a -STABLE system? Is it just a matter of running
> "zfs upgrade" and "zpool upgrade" before enabling LZ4,
or am I
> missing something? Thanks
This should work, you don't have to have the pool created on a -STABLE
system and can always do 'zpool upgrade' when necessary.

Please note that if you want to upgrade the root pool, make sure that
you have a fresh bootblock before rebooting ("zpool upgrade" should
give you a reminder).  The FreeBSD ZFS boot code supports booting from
LZ4 compressed datasets.

I would recommend using a dedicated root pool by the way, it have a
lot of advantages, like you can use a separate ZIL device for the
non-root pool, etc. and have the flexibility of using different RAID-Z
layout for different purpose (e.g. mirror for boot pool and RAID-Z for
the rest), so your remote hands would be able to just remove one disk
and your system is bootable, in the case when the first disk's boot
partition is physically damaged.

Cheers,
- -- 
Xin LI <delphij at delphij.net>    https://www.delphij.net/
FreeBSD - The Power to Serve!           Live free or die
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