[Openstack-operators] [swift] data distribution imbalance - what are the .data.XXXXX files?

Blair Bethwaite blair.bethwaite at gmail.com
Wed Jul 20 08:17:14 UTC 2016


Hi all,

As per the subject, wondering where these files come from, e.g.,:

root at stor010:/srv/node/sdc1/objects# ls -la
./109794/359/6b389b24749b7046344ffd2a42aab359
total 1195784
drwxr-xr-x 2 swift swift      4096 Jun  8 04:11 .
drwxr-xr-x 3 swift swift        53 May 22 05:05 ..
-rw------- 1 swift swift 204800000 Jun  8 04:11 1463857426.65100.data
-rw------- 1 swift swift   6225920 Jun  3 00:42 .1463857426.65100.data.aCtGLk
-rw------- 1 swift swift 197754880 Jun  2 11:49 .1463857426.65100.data.AMQhPo
-rw------- 1 swift swift  33980416 Jun  3 00:41 .1463857426.65100.data.CkpDSv
-rw------- 1 swift swift   7634944 Jun  3 04:02
.1463857426.65100.data.CkpDSv.CtrQws
-rw------- 1 swift swift 189399040 Jun  1 18:42 .1463857426.65100.data.CRFb2k
-rw------- 1 swift swift  47644672 Jun  2 11:51 .1463857426.65100.data.dKsUZI
-rw------- 1 swift swift 157122560 Jun  3 13:57 .1463857426.65100.data.GpmbOK
-rw------- 1 swift swift 174489600 Jun  2 11:50 .1463857426.65100.data.MAoI3y
-rw------- 1 swift swift 174358528 Jun  3 00:42 .1463857426.65100.data.Pbsk7S
-rw------- 1 swift swift  31064064 Jun  1 18:42 .1463857426.65100.data.xlmmie

We have a geo-replicated cluster that is currently suffering from
major outliers in disk usage, i.e.:

[2016-07-20 18:08:33] Checking disk usage now
Distribution Graph:
  0%    2 *
 32%    1
 34%   19 **********
 35%   49 **************************
 36%  127 *********************************************************************
 37%  111 ************************************************************
 38%   40 *********************
 39%   12 ******
 40%    6 ***
 41%    6 ***
 42%    2 *
 43%    4 **
 44%    3 *
 45%    1
 46%    3 *
 47%    4 **
 48%    3 *
 50%    1
 51%    2 *
 52%    1
 53%    1
 54%    1
 56%    3 *
 58%    1
 62%    2 *
 63%    1
 71%    1
 73%    1
 75%    1
 76%    1
 78%    2 *
 88%    1
 92%    2 *
 95%    1
 96%    1
 100%    3 *
Disk usage: space used: 395001580875776 of 995614295568384
Disk usage: space free: 600612714692608 of 995614295568384
Disk usage: lowest: 0.0%, highest: 100.0%, avg: 39.6741572147%

It looks like this is attributable to a handful of object directories
with lots of data.XXXXXX files in them, whereas >99% of object dirs
just have a single .data file, e.g. this from one of the disks at
~60%:

root at stor010:/srv/node/sdc1/objects# find . -mindepth 4 -type f
-printf "%h\n" | sort | uniq -c | sort -rnk 1 | head -20

    733 ./151107/3b5/9390f9c2ceee07f059a0d1f651e423b5
     11 ./109794/359/6b389b24749b7046344ffd2a42aab359
      9 ./248385/60c/f2907cb0b290def6f614bf46a715a60c
      5 ./222791/888/d991c8db1e2f1e724c1a4f52914f7888
      4 ./257772/140/fbbb1c017a841e6e821ed707025fe140
      4 ./231068/ca6/e1a706f50dd99f97fafeba6bd1f47ca6
      4 ./215734/80c/d2adbf087b09ca24cc546497d265180c
      3 ./248166/8b9/f259b3b0113b522ec5ef5753588438b9
      3 ./221060/383/d7e101fd86eeef65f8c89f3f99ce4383
      2 ./38609/203/25b46d47af8ee700e87ceab33748b203
      2 ./27961/a78/1b4e5665c16e1da8a70cc093a2bbba78
      2 ./158466/d43/9ac0b8bd4e592fe6f3360a731bac7d43
      2 ./141275/588/89f6efb554e964aeebffa9dad9e17588
      1 ./99980/fad/61a3214454426f7b30fc62773eb3bfad
      1 ./99980/fa4/61a311d12248a2e4ca8d2f61a3adafa4
      1 ./99980/ed9/61a32b429174f6099b0b35b0103e4ed9
      1 ./99980/e76/61a3129de66d7541ce127f07a7737e76
      1 ./99980/e3d/61a329332713fdacedb10834901f6e3d
      1 ./99980/e1f/61a306b87307636cc569bd0bc047ee1f
      1 ./99980/db8/61a30a00a9b7edd3318be25bbed47db8

root at stor010:/srv/node/sdc1/objects# du -sh
./151107/3b5/9390f9c2ceee07f059a0d1f651e423b5
957G    ./151107/3b5/9390f9c2ceee07f059a0d1f651e423b5

We're on version 2.5.0.7.

-- 
Cheers,
~Blairo



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