Re: mount time of multi-disk arrays

[Konstantinos Skarlatos <k.skarlatos@gmail.com>]

On 7/7/2014 5:24 μμ, André-Sebastian Liebe wrote:
> On 07/07/2014 03:54 PM, Konstantinos Skarlatos wrote:
>> On 7/7/2014 4:38 μμ, André-Sebastian Liebe wrote:
>>> Hello List,
>>>
>>> can anyone tell me how much time is acceptable and assumable for a
>>> multi-disk btrfs array with classical hard disk drives to mount?
>>>
>>> I'm having a bit of trouble with my current systemd setup, because it
>>> couldn't mount my btrfs raid anymore after adding the 5th drive. With
>>> the 4 drive setup it failed to mount once in a few times. Now it fails
>>> everytime because the default timeout of 1m 30s is reached and mount is
>>> aborted.
>>> My last 10 manual mounts took between 1m57s and 2m12s to finish.
>> I have the exact same problem, and have to manually mount my large
>> multi-disk btrfs filesystems, so I would be interested in a solution
>> as well.
> Hi Konstantinos , you can workaround this by manual creating a systemd
> mount unit.
>
> - First review the autogenerated systemd mount unit (systemctl show
> <your-mount-unit>.mount).  You you can get the unit name by issuing a
> 'systemctl' and look for your failed mount.
> - Then you have to take the needed values (After, Before, Conflicts,
> RequiresMountsFor, Where, What, Options, Type, Wantedby) and put them
> into an new systemd mount unit file (possibly under
> /usr/lib/systemd/system/<your-mount-unit>.mount ).
> - Now just add the TimeoutSec with a large enough value below [Mount].
> - If you later want to automount you raid, add the WantedBy under [Install]
> - now issue a 'systemctl daemon-reload' and look for error messages in
> syslog.
> - If there are no errors you could enable your manual mount entry by
> 'systemctl enable <your-mount-unit>.mount' and safely comment out your
> old fstab entry (systemd no longer generates autogenerated units).
>
> -- 8< ----------- 8< ----------- 8< ----------- 8< ----------- 8<
> ----------- 8< ----------- 8< -----------
> [Unit]
> Description=Mount /data/pool0
> After=dev-disk-by\x2duuid-066141c6\x2d16ca\x2d4a30\x2db55c\x2de606b90ad0fb.device
> systemd-journald.socket local-fs-pre.target system.slice -.mount
> Before=umount.target
> Conflicts=umount.target
> RequiresMountsFor=/data
> /dev/disk/by-uuid/066141c6-16ca-4a30-b55c-e606b90ad0fb
>
> [Mount]
> Where=/data/pool0
> What=/dev/disk/by-uuid/066141c6-16ca-4a30-b55c-e606b90ad0fb
> Options=rw,relatime,skip_balance,compress
> Type=btrfs
> TimeoutSec=3min
>
> [Install]
> WantedBy=dev-disk-by\x2duuid-066141c6\x2d16ca\x2d4a30\x2db55c\x2de606b90ad0fb.device
> -- 8< ----------- 8< ----------- 8< ----------- 8< ----------- 8<
> ----------- 8< ----------- 8< -----------

Hi André,
This unit file works for me, thank you for creating it! Can somebody put 
it on the wiki?




>
>
>>> My hardware setup contains a
>>> - Intel Core i7 4770
>>> - Kernel 3.15.2-1-ARCH
>>> - 32GB RAM
>>> - dev 1-4 are 4TB Seagate ST4000DM000 (5900rpm)
>>> - dev 5 is a 4TB Wstern Digital WDC WD40EFRX (5400rpm)
>>>
>>> Thanks in advance
>>>
>>> André-Sebastian Liebe
>>> --------------------------------------------------------------------------------------------------
>>>
>>>
>>> # btrfs fi sh
>>> Label: 'apc01_pool0'  uuid: 066141c6-16ca-4a30-b55c-e606b90ad0fb
>>>           Total devices 5 FS bytes used 14.21TiB
>>>           devid    1 size 3.64TiB used 2.86TiB path /dev/sdd
>>>           devid    2 size 3.64TiB used 2.86TiB path /dev/sdc
>>>           devid    3 size 3.64TiB used 2.86TiB path /dev/sdf
>>>           devid    4 size 3.64TiB used 2.86TiB path /dev/sde
>>>           devid    5 size 3.64TiB used 2.88TiB path /dev/sdb
>>>
>>> Btrfs v3.14.2-dirty
>>>
>>> # btrfs fi df /data/pool0/
>>> Data, single: total=14.28TiB, used=14.19TiB
>>> System, RAID1: total=8.00MiB, used=1.54MiB
>>> Metadata, RAID1: total=26.00GiB, used=20.20GiB
>>> unknown, single: total=512.00MiB, used=0.00
>>>
>>>
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>> -- 
>> Konstantinos Skarlatos
> --
> André-Sebastian Liebe
>


-- 
Konstantinos Skarlatos