[OpenIndiana-discuss] Replacing smaller rpool SSD with bigger one - best praxis

[stes@PANDORA.BE]

Because initially Predrag Zečević asked about ZFS with ashift 9 and ashift 12, I think this the same as

https://www.illumos.org/issues/5242

"zpool won't allow attachment of larger sector drive to mirror"

I was not aware of "zdb -C rpool" the value "ashift".

According to:

https://jrs-s.net/2018/08/17/zfs-tuning-cheat-sheet/

"Ashift tells ZFS what the underlying physical block size your disks use is. It’s in bits, so ashift=9 means 512B sectors (used by all ancient drives), ashift=12 means 4K sectors (used by most modern hard drives), and ashift=13 means 8K sectors (used by some modern SSDs)."

So I think the question that is being asked here is whether you can mirror between drives of different sector size.

According to https://www.illumos.org/issues/5242 which is flagged as 'open' this is not the case.

Regards,
David Stes



----- Op 8 mar 2023 om 11:55 schreef Discussion list for OpenIndiana openindiana-discuss at openindiana.org:

>> On 8. Mar 2023, at 02:27, Bill Sommerfeld <sommerfeld at hamachi.org> wrote:
>> 
>> On 3/7/23 13:53, gea wrote:
>>> I suppose a method based on mirror/clone + autoexpand will not work with
>>> different ashift.
>>> A disaster backup/recovery method that should work:
>>> - replicate current BE to datapool via zfs send
>>>   (you can create daily recoverable backups while OI is running with this method)
>> 
>> If you can have all the disks cabled up at the same time, you can use the '-p'
>> option to 'beadm create' to create a BE in a different pool; I've used this to
>> move the root a few times (the root pool on one of my machines is currently
>> named "r3”).
>> 
> 
> With this method, you need to keep in mind, only dataset tree from ROOT will be
> replicated. You still need to migrate/re-create other datasets like export,
> swap, dump. Also need to update dumpadm and /etc/vfstab (for swap).
> 
> rgds,
> toomas
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