[SOLVED] Squatter "No space left on device"

[Bron Gondwana]

On Tue, Jun 16, 2015, at 10:29 PM, Tecnologia Charne.Net wrote:
>
    Problem was btrfs metadata:
>
>
    cyrus squatter user/javier at unnoba.edu.ar
>
    Writing index update: No space left on device
>
>
>
    Filesystem checks:
>
>
    mda:~# btrfs filesystem df /var/spool/cyrus/
>
    Data, single: total=1.26TiB, used=349.31GiB
>
    System, DUP: total=8.00MiB, used=160.00KiB
>
    System, single: total=4.00MiB, used=0.00B
> *Metadata, DUP: total=3.50GiB, used=2.99GiB*
>
    Metadata, single: total=8.00MiB, used=0.00B
>
>
>
    btrfs filesystem usage /var/spool/cyrus
>
    Overall:
>
    Device size:           1.27TiB
>
    Device allocated:           1.27TiB
>
    Device unallocated:          60.00KiB
>
    Device missing:             0.00B
>
    Used:             355.30GiB
>
    Free (estimated):         943.69GiB    (min: 943.69GiB)
>
    Data ratio:                  1.00
>
    Metadata ratio:              2.00
>
    Global reserve:             0.00B    (used: 0.00B)
>
>
    Data,single: Size:1.26TiB, Used:349.31GiB
>
    /dev/xvdb1       1.26TiB
>
>
    Metadata,single: Size:8.00MiB, Used:0.00B
>
    /dev/xvdb1       8.00MiB
>
> *Metadata,DUP: Size:3.50GiB, Used:2.99GiB**
**   /dev/xvdb1       7.00GiB*
>
>
    System,single: Size:4.00MiB, Used:0.00B
>
    /dev/xvdb1       4.00MiB
>
>
    System,DUP: Size:8.00MiB, Used:160.00KiB
>
    /dev/xvdb1      16.00MiB
>
>
    Unallocated:
>
    /dev/xvdb1      60.00KiB
>
>
>
# btrfs balance start -v -dusage=5 /var/spool/cyrus/
>
    Dumping filters: flags 0x1, state 0x0, force is off
>
    DATA (flags 0x2): balancing, usage=5
>
    Done, had to relocate 213 out of 1302 chunks
>
>
>
    Now, it's working.

Why would anybody ever run production data on btrfs?

https://btrfs.wiki.kernel.org/index.php/Main_Page

"The Btrfs code base is under heavy development."

https://btrfs.wiki.kernel.org/index.php/Gotchas

"Files with a lot of random writes can become heavily fragmented (10000+
extents) causing trashing on HDDs and excessive multi-second spikes of
CPU load on systems with an SSD or large amount a RAM."

Unfortunately, both cyrus.index files and skiplist/twoskip databases get
a lot of random writes - though both repack occasionally which reduces
fragmentation.

I've tried other filesystems a few times, and I keep coming back to ext4
for consistent performance and crash safety (at least on decent hardware
which doesn't lie about fsync) - XFS has lost data, btrfs has always
been shiny at first, but turned into a performance disaster over time.

--
Bron Gondwana
brong at fastmail.fm
 
 
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