Date: Fri, 5 Jul 2013 00:28:07 +0100 From: "Steven Hartland" <killing@multiplay.co.uk> To: "Freddie Cash" <fjwcash@gmail.com> Cc: FreeBSD Filesystems <freebsd-fs@freebsd.org> Subject: Re: Slow resilvering with mirrored ZIL Message-ID: <3CFB4564D8EB4A6A9BCE2AFCC5B6E400@multiplay.co.uk> References: <CABBFC07-68C2-4F43-9AFC-920D8C34282E@unixconn.com><51D42107.1050107@digsys.bg><2EF46A8C-6908-4160-BF99-EC610B3EA771@alumni.chalmers.se><51D437E2.4060101@digsys.bg><E5CCC8F551CA4627A3C7376AD63A83CC@multiplay.co.uk><CBCA1716-A3EC-4E3B-AE0A-3C8028F6AACF@alumni.chalmers.se><20130704000405.GA75529@icarus.home.lan><C8C696C0-2963-4868-8BB8-6987B47C3460@alumni.chalmers.se><20130704171637.GA94539@icarus.home.lan><2A261BEA-4452-4F6A-8EFB-90A54D79CBB9@alumni.chalmers.se><20130704191203.GA95642@icarus.home.lan><43015E9015084CA6BAC6978F39D22E8B@multiplay.co.uk> <CAOjFWZ4obK1cSmvTpW%2Bt4xKdMf%2BkJV5w-sujDT1AZoepj%2B5YrA@mail.gmail.com>
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----- Original Message -----
From: "Freddie Cash" <fjwcash@gmail.com>
>>> 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?
This should have read "at least one of the devices your adding as a new vdev
to the pool"
> "... 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.
If anyone wants my current patches which add switch to 4k ashift by default
as a sysctl + works with QUIRKS too, just let me know.
They are well tested, just we want more options before putting in the tree.
Regards
Steve
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