Is TRIM working with gmirror?

[Steven Hartland]

----- Original Message ----- 
From: "Miroslav Lachman" <000.fbsd at quip.cz>
To: "Steven Hartland" <killing at multiplay.co.uk>
Cc: "Karl Pielorz" <kpielorz_lst at tdx.co.uk>; <freebsd-geom at FreeBSD.org>
Sent: Tuesday, January 07, 2014 12:10 PM
Subject: Re: Is TRIM working with gmirror?


> 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.

    Regards
    Steve

================================================
This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it. 

In the event of misdirection, illegible or incomplete transmission please telephone +44 845 868 1337
or return the E.mail to postmaster at multiplay.co.uk.