Skip site navigation (1)Skip section navigation (2)
Date:      Wed, 08 Jan 2014 16:00:07 +0100
From:      Miroslav Lachman <000.fbsd@quip.cz>
To:        Steven Hartland <killing@multiplay.co.uk>
Cc:        Karl Pielorz <kpielorz_lst@tdx.co.uk>, freebsd-geom@FreeBSD.org
Subject:   Re: Is TRIM working with gmirror?
Message-ID:  <52CD67F7.2060608@quip.cz>
In-Reply-To: <C38DE9655CBB41029AF5CF0583CD2ACC@multiplay.co.uk>
References:  <52A90049.7050001@quip.cz> <18C59233568D3A475FF0D843@study64.tdx.co.uk> <52CB2915.7060602@quip.cz> <7FBCC53840FA45928B9F527EA235B632@multiplay.co.uk> <52CB4C9E.3020904@quip.cz> <41F7CA403B574953B72B6CF4D1DDE71D@multiplay.co.uk> <52CBEE9E.2090800@quip.cz> <353E7C512D234EDE84863C872D7856DE@multiplay.co.uk> <C38DE9655CBB41029AF5CF0583CD2ACC@multiplay.co.uk>

next in thread | previous in thread | raw e-mail | index | archive | help
Steven Hartland wrote:
> ----- Original Message ----- From: "Steven Hartland"
> <killing@multiplay.co.uk>
>
>> ----- Original Message ----- From: "Miroslav Lachman" <000.fbsd@quip.cz>
>>
>>> Steven Hartland wrote:
>>> [...]
>>>> Unless you have a specific reason for using gmirror I would strongly
>>>> advise trying ZFS instead, it will definitely support TRIM in that
>>>> config and comes with a host of other benefits too :)
>>>
>>> The specific reason is performance and memory consumption. We need
>>> every piece of performance and all memory to MySQL daemon, so this is
>>> why gmirror was choosen.
>>> We have ZFS on other purposes machines for years (from 7.x days), so
>>> I can say "I have a lot of experiences" (good and bad too).
>>> In some tests, ZFS is about 50% slower than UFS.
>>>
>>> What about graid(8) mirror instead of gmirror(8)? Is there better
>>> support for TRIM on UFS?
>>
>> Actually looking at it gmirror should support delete no problem see
>> g_mirror_init_disk GEOM::candelete.
>>
>> So you might want to add some debugging around there to see whats
>> happening.
>
> Double checked this on HEAD and it definitely works as expected.

I am not able to understand C sources, so I cannot check it myself. But 
if it is supported, why I see the warning message at boot?

Miroslav Lachman



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?52CD67F7.2060608>