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From: Arshavir Grigorian <ag@m-cam.com>
To: linux-raid@vger.kernel.org, pgsql-performance@postgresql.org
Subject: Postgres on RAID5
Date: Fri, 11 Mar 2005 14:48:02 -0500	[thread overview]
Message-ID: <4231F5F2.6000509@m-cam.com> (raw)

Hi,

I have a RAID5 array (mdadm) with 14 disks + 1 spare. This partition has 
an Ext3 filesystem which is used by Postgres. Currently we are loading a 
50G database on this server from a Postgres dump (copy, not insert) and 
are experiencing very slow write performance (35 records per second).

Top shows that the Postgres process (postmaster) is being constantly put 
into D state for extended periods of time (2-3 seconds) which I assume 
is because it's waiting for disk io. I have just started gathering 
system statistics and here is what sar -b shows: (this is while the db 
is being loaded - pg_restore)

  	       tps        rtps     wtps      bread/s  bwrtn/s
01:35:01 PM    275.77     76.12    199.66    709.59   2315.23
01:45:01 PM    287.25     75.56    211.69    706.52   2413.06
01:55:01 PM    281.73     76.35    205.37    711.84   2389.86
02:05:01 PM    282.83     76.14    206.69    720.85   2418.51
02:15:01 PM    284.07     76.15    207.92    707.38   2443.60
02:25:01 PM    265.46     75.91    189.55    708.87   2089.21
02:35:01 PM    285.21     76.02    209.19    709.58   2446.46
Average:       280.33     76.04    204.30    710.66   2359.47

This is a Sun e450 with dual TI UltraSparc II processors and 2G of RAM. 
It is currently running Debian Sarge with a 2.4.27-sparc64-smp custom 
compiled kernel. Postgres is installed from the Debian package and uses 
all the configuration defaults.

I am also copying the pgsql-performance list.

Thanks in advance for any advice/pointers.


Arshavir

Following is some other info that might be helpful.

/proc/scsi# mdadm -D /dev/md1
/dev/md1:
         Version : 00.90.00
   Creation Time : Wed Feb 23 17:23:41 2005
      Raid Level : raid5
      Array Size : 123823616 (118.09 GiB 126.80 GB)
     Device Size : 8844544 (8.43 GiB 9.06 GB)
    Raid Devices : 15
   Total Devices : 17
Preferred Minor : 1
     Persistence : Superblock is persistent

     Update Time : Thu Feb 24 10:05:38 2005
           State : active
  Active Devices : 15
Working Devices : 16
  Failed Devices : 1
   Spare Devices : 1

          Layout : left-symmetric
      Chunk Size : 64K

            UUID : 81ae2c97:06fa4f4d:87bfc6c9:2ee516df
          Events : 0.8

     Number   Major   Minor   RaidDevice State
        0       8       64        0      active sync   /dev/sde
        1       8       80        1      active sync   /dev/sdf
        2       8       96        2      active sync   /dev/sdg
        3       8      112        3      active sync   /dev/sdh
        4       8      128        4      active sync   /dev/sdi
        5       8      144        5      active sync   /dev/sdj
        6       8      160        6      active sync   /dev/sdk
        7       8      176        7      active sync   /dev/sdl
        8       8      192        8      active sync   /dev/sdm
        9       8      208        9      active sync   /dev/sdn
       10       8      224       10      active sync   /dev/sdo
       11       8      240       11      active sync   /dev/sdp
       12      65        0       12      active sync   /dev/sdq
       13      65       16       13      active sync   /dev/sdr
       14      65       32       14      active sync   /dev/sds

       15      65       48       15      spare   /dev/sdt

# dumpe2fs -h /dev/md1
dumpe2fs 1.35 (28-Feb-2004)
Filesystem volume name:   <none>
Last mounted on:          <not available>
Filesystem UUID:          1bb95bd6-94c7-4344-adf2-8414cadae6fc
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal dir_index needs_recovery large_file
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              15482880
Block count:              30955904
Reserved block count:     1547795
Free blocks:              28767226
Free inodes:              15482502
First block:              0
Block size:               4096
Fragment size:            4096
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         16384
Inode blocks per group:   512
Filesystem created:       Wed Feb 23 17:27:13 2005
Last mount time:          Wed Feb 23 17:45:25 2005
Last write time:          Wed Feb 23 17:45:25 2005
Mount count:              2
Maximum mount count:      28
Last checked:             Wed Feb 23 17:27:13 2005
Check interval:           15552000 (6 months)
Next check after:         Mon Aug 22 18:27:13 2005
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               128
Journal inode:            8
Default directory hash:   tea
Directory Hash Seed:      c35c0226-3b52-4dad-b102-f22feb773592
Journal backup:           inode blocks

# lspci | grep SCSI
0000:00:03.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875 
(rev 14)
0000:00:03.1 SCSI storage controller: LSI Logic / Symbios Logic 53c875 
(rev 14)
0000:00:04.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875 
(rev 14)
0000:00:04.1 SCSI storage controller: LSI Logic / Symbios Logic 53c875 
(rev 14)
0000:04:02.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875 
(rev 03)
0000:04:03.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875 
(rev 03)

/proc/scsi# more scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
   Vendor: SEAGATE  Model: ST39103LCSUN9.0G Rev: 034A
   Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 01 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi0 Channel: 00 Id: 02 Lun: 00
   Vendor: SEAGATE  Model: ST39103LCSUN9.0G Rev: 034A
   Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 03 Lun: 00
   Vendor: SEAGATE  Model: ST39103LCSUN9.0G Rev: 034A
   Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 00
   Vendor: SEAGATE  Model: ST39103LCSUN9.0G Rev: 034A
   Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 01 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi1 Channel: 00 Id: 02 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi1 Channel: 00 Id: 03 Lun: 00
   Vendor: SEAGATE  Model: ST39103LCSUN9.0G Rev: 034A
   Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi2 Channel: 00 Id: 00 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi2 Channel: 00 Id: 01 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi2 Channel: 00 Id: 02 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi2 Channel: 00 Id: 03 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi3 Channel: 00 Id: 00 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi3 Channel: 00 Id: 01 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi3 Channel: 00 Id: 02 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi3 Channel: 00 Id: 03 Lun: 00
   Vendor: SEAGATE  Model: ST39204LCSUN9.0G Rev: 4207
   Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi4 Channel: 00 Id: 06 Lun: 00
   Vendor: TOSHIBA  Model: XM6201TASUN32XCD Rev: 1103
   Type:   CD-ROM                           ANSI SCSI revision: 02
Host: scsi5 Channel: 00 Id: 00 Lun: 00
   Vendor: FUJITSU  Model: MAG3091L SUN9.0G Rev: 1111
   Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi5 Channel: 00 Id: 01 Lun: 00
   Vendor: FUJITSU  Model: MAG3091L SUN9.0G Rev: 1111
   Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi5 Channel: 00 Id: 02 Lun: 00
   Vendor: FUJITSU  Model: MAG3091L SUN9.0G Rev: 1111
   Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi5 Channel: 00 Id: 03 Lun: 00
   Vendor: FUJITSU  Model: MAG3091L SUN9.0G Rev: 1111
   Type:   Direct-Access                    ANSI SCSI revision: 02






-- 
Arshavir Grigorian
Systems Administrator/Engineer

             reply	other threads:[~2005-03-11 19:48 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-03-11 19:48 Arshavir Grigorian [this message]
2005-03-14  4:36 ` [PERFORM] Postgres on RAID5 Greg Stark
2005-03-14  7:44   ` [PERFORM] Postgres on RAID5 (possible sync blocking read type issue on 2.6.11) David Greaves
2005-03-14 19:53   ` [PERFORM] Postgres on RAID5 Alex Turner
2005-03-14 20:17     ` Greg Stark
2005-03-14 20:35       ` Jim Buttafuoco
2005-03-14 21:03     ` Arshavir Grigorian
2005-03-14 22:47       ` Michael Tokarev
2005-03-14 23:49         ` Guy
2005-03-15 16:17           ` Effect of Stripe Size (was Postgres on RAID5) Ruth Ivimey-Cook
2005-03-16 16:47 ` Postgres on RAID5 David Dougall
2005-03-16 16:55   ` Michael Tokarev
  -- strict thread matches above, loose matches on Subject: below --
2005-03-11 21:18 Arshavir Grigorian

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