[Gluster-users] GlusterFS (3.3.1) - performance issues - large number of LOOKUP calls & high CPU usage

Charles Cooke charles at coupa.com
Tue May 28 00:20:47 UTC 2013


Hi,

We are currently attempting to use GlusterFS but are encountering
significant performance issues in our environment.  The symptoms we are
seeing are that read/write performance degrades and the glusterfsd
eventually takes up to 100% of the CPU.

We currently run in a simple 1x2 replicated configuration.  The I/O
primarily consists of write operations, with a smaller amount of reads.

What we see consistently on profiling is that the LOOKUP calls are
consistently taking the majority of the time.  I am not sure what this
represents - but the ordinality seems to be out of whack - eg. when several
dozen read/write operations are taking place, there will be several
thousand LOOKUP calls.

Following the discussion in the IRC Archives - there was some indication
that our symptoms (large number of LOOKUP calls) were the result of
self-heal checks and/or DHT misses as per:
http://irclog.perlgeek.de/gluster/2012-11-28
--> JoeJulian Well, that's either self-heal checks and/or dht misses.

So we've disabled the self-heal daemon and turned lookup-unhashed off.  But
this hasn't had an impact on the performance either way.  The volume
information is shown below along with volume profiling information.

Volume Name: gluster
Type: Replicate
Volume ID: 08cb1e95-1f56-449c-b427-8f1921371d5a
Status: Started
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: stg100mol1-int.coupahost.com:/mnt/gluster/export
Brick2: stg100mol2-int.coupahost.com:/mnt/gluster/export
Options Reconfigured:
performance.cache-size: 2000000000
performance.cache-refresh-timeout: 0
geo-replication.indexing: off
diagnostics.latency-measurement: on
diagnostics.count-fop-hits: on
cluster.self-heal-daemon: off
cluster.lookup-unhashed: off


Brick: stg100mol1-int.coupahost.com:/mnt/gluster/export
-------------------------------------------------------
Cumulative Stats:
   Block Size:                  1b+                   2b+
4b+
 No. of Reads:                    0                     0
  0
No. of Writes:                   98                     8
 69

   Block Size:                  8b+                  16b+
 32b+
 No. of Reads:                    0                     0
  0
No. of Writes:                  125                    43
  7

   Block Size:                 64b+                 128b+
256b+
 No. of Reads:                    3                     0
 18
No. of Writes:                  154                   620
262

   Block Size:                512b+                1024b+
 2048b+
 No. of Reads:                   27                    68
 14
No. of Writes:                  373                    86
 60

   Block Size:               4096b+                8192b+
16384b+
 No. of Reads:                    0                     6
 14
No. of Writes:                11957                  2398
  6

   Block Size:              32768b+               65536b+
 131072b+
 No. of Reads:                   17                    65
149
No. of Writes:                    7                     0
  0

 %-latency   Avg-latency   Min-Latency   Max-Latency   No. of calls
Fop
 ---------   -----------   -----------   -----------   ------------
 ----
      0.00       0.00 us       0.00 us       0.00 us            712
 FORGET
      0.00       0.00 us       0.00 us       0.00 us           5789
RELEASE
      0.00       0.00 us       0.00 us       0.00 us           5896
 RELEASEDIR
      0.00      86.33 us      52.00 us     137.00 us              3
 GETXATTR
      0.00    1045.00 us    1045.00 us    1045.00 us              1
RMDIR
      0.00     156.98 us      32.00 us    1272.00 us             41
FTRUNCATE
      0.00     572.24 us     212.00 us    3865.00 us             49
MKDIR
      0.01     135.47 us      36.00 us    6126.00 us            471
 TRUNCATE
      0.01     160.58 us      14.00 us    5641.00 us            470
 STAT
      0.03     517.82 us      38.00 us  163774.00 us            471
SETATTR
      0.07    1445.84 us      25.00 us   97172.00 us            396
 READ
      0.07     401.11 us      13.00 us   33647.00 us           1449
READDIR
      0.10    3617.81 us     111.00 us  237368.00 us            221
 STATFS
      0.10    8252.17 us      14.00 us  406281.00 us             99
 LK
      0.10    1161.94 us     162.00 us  263151.00 us            709
 CREATE
      0.12    2204.37 us      79.00 us  175090.00 us            457
 RENAME
      0.13    1084.25 us      84.00 us  487294.00 us            942
XATTROP
      0.24     336.51 us      23.00 us  753796.00 us           5896
OPENDIR
      0.25     343.05 us      25.00 us  267306.00 us           5951
 OPEN
      0.26     763.13 us      12.00 us  498524.00 us           2729
INODELK
      0.26     518.81 us      11.00 us  574717.00 us           4100
ENTRYLK
      0.27    5757.93 us      65.00 us  266003.00 us            377
 UNLINK
      0.28     141.80 us      25.00 us   33487.00 us          16273
WRITE
      0.38     303.52 us      12.00 us  905949.00 us          10244
FSTAT
      0.88   14109.27 us    1733.00 us  574868.00 us            505
FSYNC
      2.17    1793.98 us       7.00 us 1341172.00 us           9841
FLUSH
      3.17     788.24 us      66.00 us  925523.00 us          32627
 FXATTROP
     13.92    7132.57 us      55.00 us  735763.00 us          15853
 READDIRP
     18.04    2726.17 us       7.00 us 1337047.00 us          53762
 FINODELK
     59.14     630.92 us      29.00 us 1358867.00 us         761500
 LOOKUP

    Duration: 2281 seconds
   Data Read: 27416867 bytes
Data Written: 115562427 bytes

Interval 47 Stats:
   Block Size:               4096b+                8192b+
 No. of Reads:                    0                     0
No. of Writes:                  104                    21
 %-latency   Avg-latency   Min-Latency   Max-Latency   No. of calls
Fop
 ---------   -----------   -----------   -----------   ------------
 ----
      0.00       0.00 us       0.00 us       0.00 us              7
RELEASE
      0.00       0.00 us       0.00 us       0.00 us             21
 RELEASEDIR
      0.00      18.86 us      13.00 us      36.00 us              7
FLUSH
      0.00      38.00 us      15.00 us      67.00 us              4
ENTRYLK
      0.00     230.00 us     230.00 us     230.00 us              1
MKDIR
      0.00     251.00 us     251.00 us     251.00 us              1
 CREATE
      0.01     116.50 us      33.00 us     455.00 us              6
 OPEN
      0.01     133.83 us      23.00 us     260.00 us              6
 STAT
      0.02     827.50 us     139.00 us    1516.00 us              2
 STATFS
      0.03     103.95 us      31.00 us     284.00 us             21
OPENDIR
      0.07     339.07 us      66.00 us     907.00 us             14
 READDIRP
      0.08      89.11 us      20.00 us     750.00 us             64
FSTAT
      0.23     123.34 us      48.00 us     901.00 us            125
WRITE
      0.41     105.09 us      16.00 us    2021.00 us            263
 FINODELK
      0.86     234.20 us      73.00 us    8309.00 us            249
 FXATTROP
     98.27     794.98 us      32.00 us  372846.00 us           8420
 LOOKUP

    Duration: 11 seconds
   Data Read: 0 bytes
Data Written: 993600 bytes

Brick: stg100mol2-int.coupahost.com:/mnt/gluster/export
-------------------------------------------------------
Cumulative Stats:
   Block Size:                  1b+                   2b+
4b+
 No. of Reads:                    0                     0
  0
No. of Writes:                   98                     8
 69

   Block Size:                  8b+                  16b+
 32b+
 No. of Reads:                    0                     0
  0
No. of Writes:                  125                    43
  7

   Block Size:                 64b+                 128b+
256b+
 No. of Reads:                    0                     3
 13
No. of Writes:                  154                   620
262

   Block Size:                512b+                1024b+
 2048b+
 No. of Reads:                   32                    58
 15
No. of Writes:                  373                    86
 60

   Block Size:               4096b+                8192b+
16384b+
 No. of Reads:                    0                     6
 16
No. of Writes:                11957                  2398
  6

   Block Size:              32768b+               65536b+
 131072b+
 No. of Reads:                   19                    46
163
No. of Writes:                    7                     0
  0

 %-latency   Avg-latency   Min-Latency   Max-Latency   No. of calls
Fop
 ---------   -----------   -----------   -----------   ------------
 ----
      0.00       0.00 us       0.00 us       0.00 us            712
 FORGET
      0.00       0.00 us       0.00 us       0.00 us           5789
RELEASE
      0.00       0.00 us       0.00 us       0.00 us           5896
 RELEASEDIR
      0.00     131.00 us     131.00 us     131.00 us              1
RMDIR
      0.00      87.00 us      61.00 us     113.00 us              2
 GETXATTR
      0.00     197.12 us      32.00 us    2304.00 us             41
FTRUNCATE
      0.01     602.80 us     214.00 us   11089.00 us             49
MKDIR
      0.01     105.21 us      38.00 us    4226.00 us            471
 TRUNCATE
      0.01     514.50 us      17.00 us   44276.00 us             98
 LK
      0.03     369.86 us      14.00 us   35614.00 us            322
 STAT
      0.07     618.82 us      38.00 us  230853.00 us            471
SETATTR
      0.07     427.43 us     172.00 us   21070.00 us            709
 CREATE
      0.13     589.38 us     107.00 us   47276.00 us            942
XATTROP
      0.15    3001.27 us     111.00 us  600028.00 us            221
 STATFS
      0.18     284.42 us      11.00 us  230739.00 us           2725
INODELK
      0.24    2732.04 us      23.00 us   85370.00 us            385
 READ
      0.27    2572.42 us      75.00 us  256620.00 us            457
 RENAME
      0.33     239.45 us      24.00 us  625901.00 us           5951
 OPEN
      0.37     169.74 us      15.00 us  433133.00 us           9356
FSTAT
      0.39    1164.77 us      14.00 us  468495.00 us           1449
READDIR
      0.44    5045.44 us     121.00 us   89320.00 us            377
 UNLINK
      0.46     339.88 us      21.00 us  632652.00 us           5896
OPENDIR
      0.55     145.86 us      25.00 us  123050.00 us          16273
WRITE
      0.76     803.77 us      11.00 us  857743.00 us           4100
ENTRYLK
      1.69   14534.79 us    1493.00 us  464961.00 us            505
FSYNC
      4.71    2078.22 us       6.00 us  818633.00 us           9841
FLUSH
      5.05    2310.54 us      56.00 us  615643.00 us           9497
 READDIRP
      5.95     791.32 us      63.00 us  608936.00 us          32628
 FXATTROP
      6.97     563.13 us       6.00 us 1103183.00 us          53723
 FINODELK
     71.18     405.92 us       8.00 us 1216554.00 us         761502
 LOOKUP

    Duration: 2250 seconds
   Data Read: 27138474 bytes
Data Written: 115562427 bytes

Interval 47 Stats:
   Block Size:               4096b+                8192b+
 No. of Reads:                    0                     0
No. of Writes:                  104                    21
 %-latency   Avg-latency   Min-Latency   Max-Latency   No. of calls
Fop
 ---------   -----------   -----------   -----------   ------------
 ----
      0.00       0.00 us       0.00 us       0.00 us              7
RELEASE
      0.00       0.00 us       0.00 us       0.00 us             21
 RELEASEDIR
      0.00      26.00 us      26.00 us      26.00 us              1
 STAT
      0.00     195.00 us     195.00 us     195.00 us              1
 CREATE
      0.00      53.25 us      27.00 us      86.00 us              4
ENTRYLK
      0.00     249.00 us     249.00 us     249.00 us              1
MKDIR
      0.00     159.00 us     125.00 us     193.00 us              2
 STATFS
      0.01      52.00 us      18.00 us     143.00 us              7
FLUSH
      0.01      65.67 us      33.00 us     136.00 us              6
 OPEN
      0.03      98.14 us      25.00 us     405.00 us             21
OPENDIR
      0.04      50.35 us      18.00 us     202.00 us             57
FSTAT
      0.17     381.32 us      77.00 us     926.00 us             28
 READDIRP
      0.26     134.29 us      50.00 us    1403.00 us            125
WRITE
      0.93     240.55 us      71.00 us   10168.00 us            250
 FXATTROP
      0.98     240.87 us      15.00 us   34353.00 us            264
 FINODELK
     97.56     749.24 us      28.00 us  296964.00 us           8417
 LOOKUP

    Duration: 11 seconds
   Data Read: 0 bytes
Data Written: 993600 bytes




-- 
Thank You,

Charles Cooke
Senior Cloud Software Engineer
Coupa Software | www.coupa.com
charles.cooke at coupa.com
Cell: 902.452.4858
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