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 12:38 AM
Subject: Re: Is TRIM working with gmirror?


> Steven Hartland wrote:
> [...]
>> Delete's are only support by CAM currently so if your device is
>> not connected to a CAM based driver e.g. daX or adaX then its
>> likely not getting through to the device.
> 
> It was mentioned in an original message:
> 
> mirror/gm1ssdp2  COMPLETE  ada2p2 (ACTIVE)
>                            ada3p2 (ACTIVE)
> 
> So disks are using CAM (devices ada2 + ada3, with ahci_load="YES" in 
> loader.conf)
> 
> # camcontrol devlist
> ..
> ..
> <Samsung SSD 840 PRO Series DXM05B0Q>  at scbus2 target 0 lun 0 (pass2,ada2)
> <Samsung SSD 840 PRO Series DXM05B0Q>  at scbus3 target 0 lun 0 (pass3,ada3)
> 
>> Not sure if this has been mentioned but you also need to have
>> filesystem support, as your talking about gmirror I assume your
>> using UFS which would need to be TRIM enabled using tunefs -t enable,
>> see man tunefs for more info.
> 
> Gmirror and FS was created on testmachine with FreeBSD 9.2 with 
> following commands:
> 
> 
>     gmirror label -v -b load gm1ssdp2 ada2p2 ada3p2
> 
>     newfs -U -L Rtzt0ssddb -t mirror/gm1ssdp2
> 
> And as WARNING message says, FS is flagged with TRIM support enabled:
> 
> --------------
> WARNING: /ssd_db: TRIM flag on fs but disk does not confirm that it 
> supports TRIM
> --------------

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 :)

    Regards
    Steve

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