Slow resilvering with mirrored ZIL

[Freddie Cash]

On Thu, Jul 4, 2013 at 12:41 PM, Steven Hartland <killing at multiplay.co.uk>wrote:

> ----- Original Message ----- From: "Jeremy Chadwick" <jdc at koitsu.org>
> ...
>
>> I believe -- but I need someone else to chime in here with confirmation,
>> particularly someone who is familiar with ZFS's internals -- once your
>> pool is ashift 12, you can do a disk replacement ***without*** having to
>> do the gnop procedure (because the pool itself is already using ashift
>> 12).  But again, I need someone to confirm that.
>>
>
> Close, the ashift is a property of the vdev and not the entire pool so
> if your adding a new vdev to the pool at least one of the devices in
> said pool needs to report 4k sectors either natively or via the gnop
>
    ^^^^^^^^^^^^


> work around.
>

Typo?

"... so if you're adding a new vdev to the pool at least one of the devices
in
said VDEV needs to report ..."

I made the mistake of thinking ashift was a property of the pool and added
3x 6-drive raidz2 vdevs to an existing pool of 4x 6-drive raidz vdevs
without using gnop .... and now have 3 vdevs with ashift=9 and 4 vdevs with
ashift=12.  :(  Here's hoping the box gets replaced before 512b drives are
discontinued completely ...

I now have it on my "zpool add" checklist to always use gnop devices,
regardless of what kind of drive is being used.

-- 
Freddie Cash
fjwcash at gmail.com