Migrating ZFS from 8.3 to 10.1

[javocado]

Thank you for that info.

A couple more questions...

So would this sequence go like this?:

freebsd 8.3# zpool export tank

(shut down)

(replace boot device with new device pre-loaded with 10.1)

(boot up to 10.1)

freebsd 10.1# zpool upgrade tank
freebsd 10.1# zpool import tank

And that command should complete quickly, regardless of the size of the
pool, number of inodes, etc, correct?


Next, we would want to consider what's involved with upgrading the zfs
filesystems. We have many filesystems (~500-1000) with 40-70 TB of data
(pool just under 100 TB in size) with thousands of snapshots (evenly spread
amongst the filesystems), and some filesystems are very dense with millions
of inodes.

- What are the advantages, disadvantages, pitfalls and caveats to be aware
of here? We know that the filesystems will no longer be readable by older
systems. Is there anything else?

- We wonder if the time it will take to upgrade all these is substantial-
i.e. will the upgrade parse through all this data in each filesystem or
just flip a few switches in each filesystem, completing quickly?

- Any impact on the (old) snapshots already in place? Any issues with
having a mix of old and new (post upgrade) snapshots in a filesystem?




On Sat, Apr 11, 2015 at 8:31 PM, Shane Ambler <FreeBSD at shaneware.biz> wrote:

> On 11/04/2015 07:13, javocado wrote:
>
>> Hello,
>>
>> I am planning to migrate (upgrade) my system from FreeBSD 8.3 RELEASE to
>> 10.1 RELEASE (both amd64). My zfs pool exists on it's own physical
>> device(s) so my upgrade will consist of:
>>
>> 1. install FreeBSD 10.1 on boot device (in a temp system)
>> 2. remove 8.3 boot device (from production system)
>> 3. install new 10.1 boot device and boot up production system
>> 4. re-mount zfs FS
>>
>> My question is, what do I need to know about how this change will affect
>> or
>> impact the zpool and datasets? Is there any chance zfs data could be lost
>> or destroyed? Might there be a performance loss due to version
>> differences?
>> Is upgrading the zpool (once booted to 10.1) strongly advised? Any
>> downsides or dangers there?
>>
>
> Once you upgrade your zpool in 10.1 you can't mount it in < 10.1
> I think you can selectively enable features if you want to keep old
> system compatibility. Not sure if there is a list of what features are
> available for each system version.
>
> Exporting your zpool as you shutdown 8.x will make it easier to import
> into 10.1
>
>
>  Some other info worth considering (production system):
>>
>> ZFS filesystem version 5
>> ZFS storage pool version 28
>>
>> Thanks!
>>
>
>
> --
> FreeBSD - the place to B...Storing Data
>
> Shane Ambler
>
>