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* Abysmal Performance
@ 2011-06-20 21:51 Henning Rohlfs
  2011-06-21  0:12 ` Josef Bacik
                   ` (2 more replies)
  0 siblings, 3 replies; 37+ messages in thread
From: Henning Rohlfs @ 2011-06-20 21:51 UTC (permalink / raw)
  To: linux-btrfs

[-- Attachment #1: Type: text/plain, Size: 3052 bytes --]

 Hello,

 I've migrated my system to btrfs (raid1) a few months ago. Since then 
 the performance has been pretty bad, but recently it's gotten 
 unbearable: a simple sync called while the system is idle can take 20 up 
 to 60 seconds. Creating or deleting files often has several seconds 
 latency, too.

 One curious - but maybe unrelated - observation is that even though I'm 
 using a raid1 btrfs setup, the hdds are often being written to 
 sequentially. One hard-drive sees some write activity and after it 
 subsides, the other drive sees some activity. (See attached 
 sequential-writes.txt.)

 - 64bit gentoo with vanilla 2.6.39 kernel
 - lzo compression enabled
 - 2x WD1000FYPS (1TB WD hdds)
 - Athlon x2 2.2GHz with 8GB RAM
 - space_cache was enabled, but it seemed to make the problem worse. 
 It's no longer in the mount options.

 Any help is appreciated. Thanks,
 Henning




 server ~ # sync; time sync
 real	0m28.869s
 user	0m0.000s
 sys	0m5.750s



 server ~ # uname -a
 Linux server 2.6.39 #3 SMP Sat May 28 17:25:31 CEST 2011 x86_64 AMD 
 Athlon(tm) 64 X2 Dual Core Processor 4200+ AuthenticAMD GNU/Linux



 server ~ # mount | grep btrfs
 /dev/sdb2 on / type btrfs (rw,noatime,compress=lzo,noacl)
 /dev/sda2 on /mnt/pool type btrfs (rw,noatime,subvolid=0,compress=lzo)
 /dev/sda2 on /usr/portage type btrfs 
 (rw,noatime,subvol=newportage,compress=lzo)
 /dev/sda2 on /home type btrfs (rw,noatime,subvol=home,compress=lzo)
 /dev/sda2 on /home/mythtv type btrfs 
 (rw,noatime,subvol=mythtv,compress=lzo)



 server ~ # btrfs fi show
 Label: none  uuid: 7676eb78-e411-4505-ac51-ccd12aa5a6b6
 	Total devices 2 FS bytes used 281.58GB
 	devid    1 size 931.28GB used 898.26GB path /dev/sda2
 	devid    3 size 931.27GB used 898.26GB path /dev/sdb2

 Btrfs v0.19-35-g1b444cd-dirty



 server ~ # btrfs fi df /
 Data, RAID1: total=875.00GB, used=279.30GB
 System, RAID1: total=8.00MB, used=140.00KB
 System: total=4.00MB, used=0.00
 Metadata, RAID1: total=23.25GB, used=2.28GB



 bonnie++

 Version  1.96       ------Sequential Output------ --Sequential Input- 
 --Random-
 Concurrency   1     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- 
 --Seeks--
 Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  
 /sec %CP
 server          16G   147  90 76321  18 31787  16  1370  71 64812  14  
 27.0  66
 Latency             66485us    7581ms    4455ms   25011us     695ms     
 959ms
 Version  1.96       ------Sequential Create------ --------Random 
 Create--------
 server              -Create-- --Read--- -Delete-- -Create-- --Read--- 
 -Delete--
               files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  
 /sec %CP
                  16   238  51 +++++ +++   219  51   284  52 +++++ +++   
 390  57
 Latency              1914ms     524us    3461ms    1141ms      39us    
 1308ms
 1.96,1.96,server,1,1308618030,16G,,147,90,76321,18,31787,16,1370,71,64812,14,27.0,66,16,,,,,238,51,+++++,+++,219,51,284,52,+++++,+++,390,57,66485us,7581ms,4455ms,25011us,695ms,959ms,1914ms,524us,3461ms,1141ms,39us,1308ms

[-- Attachment #2: sequential-writes.txt --]
[-- Type: text/plain, Size: 2015 bytes --]

server ~ # iostat -m 5

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           3.00    0.00   45.20    5.20    0.00   46.60

Device:            tps    MB_read/s    MB_wrtn/s    MB_read    MB_wrtn
sda               0.00         0.00         0.00          0          0
sdb              15.20         0.06         0.00          0          0
md0               0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           4.30    0.00   37.46   42.36    0.00   15.88

Device:            tps    MB_read/s    MB_wrtn/s    MB_read    MB_wrtn
sda              45.00         0.00         0.38          0          1
sdb             467.60         0.02         2.06          0         10
md0               0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           4.31    0.00   19.34   58.82    0.00   17.54

Device:            tps    MB_read/s    MB_wrtn/s    MB_read    MB_wrtn
sda               8.80         0.00         0.04          0          0
sdb             649.80         0.02         2.67          0         13
md0               0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           3.20    0.00   63.24   31.97    0.00    1.60

Device:            tps    MB_read/s    MB_wrtn/s    MB_read    MB_wrtn
sda             585.80         0.00         2.36          0         11
sdb              20.80         0.08         0.16          0          0
md0               0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           3.30    0.00   42.60   39.30    0.00   14.80

Device:            tps    MB_read/s    MB_wrtn/s    MB_read    MB_wrtn
sda             514.20         0.00         2.29          0         11
sdb              59.20         0.10         0.17          0          0
md0               0.00         0.00         0.00          0          0



^ permalink raw reply	[flat|nested] 37+ messages in thread
* abysmal performance
@ 2011-04-29 14:46 John Wyzer
  2011-04-29 15:01 ` Chris Mason
  0 siblings, 1 reply; 37+ messages in thread
From: John Wyzer @ 2011-04-29 14:46 UTC (permalink / raw)
  To: linux-btrfs

Currently on 
commit 7cf96da3ec7ca225acf4f284b0e904a1f5f98821
Author: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Date:   Mon Apr 25 19:43:53 2011 -0400
    Btrfs: cleanup error handling in inode.c

merged into 2.6.38.4

I'm on a btrfs filesystem that has been used for some time. Let's say nine 
months. Very recently I noticed performance getting worse and worse.
Most of the time it feels as if the system is just busy with iowait.
Write and read performance during random access is mostly around 2MB/s,
sometimes 1MB/s or slower. It's better for big files which can be read with about
6-9MB/s. The disk is a reasonably recent SATA disk (WDC_WD3200BEVT) so 30MB/s
or 40MB/s linear reading should not be a problem.

rootfs                291G  242G   35G  88% /

I tried  btrfs filesystem defragment -v / but did not notice any improvement 
after that.

Is this a known phenomenon? :-)


^ permalink raw reply	[flat|nested] 37+ messages in thread
end of thread, other threads:[~2011-06-22 15:58 UTC | newest]

Thread overview: 37+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-06-20 21:51 Abysmal Performance Henning Rohlfs
2011-06-21  0:12 ` Josef Bacik
2011-06-21  7:10   ` Henning Rohlfs
2011-06-21  8:00 ` Sander
2011-06-21  9:26   ` Henning Rohlfs
2011-06-21 15:18     ` Josef Bacik
2011-06-21 16:55       ` Henning Rohlfs
2011-06-21 15:24 ` Calvin Walton
2011-06-22 14:15   ` Henning Rohlfs
2011-06-22 15:39     ` Josef Bacik
2011-06-22 15:57       ` Calvin Walton
2011-06-22 15:58         ` Josef Bacik
  -- strict thread matches above, loose matches on Subject: below --
2011-04-29 14:46 abysmal performance John Wyzer
2011-04-29 15:01 ` Chris Mason
2011-04-30 17:33   ` Mitch Harder
2011-04-30 20:40     ` John Wyzer
2011-04-30 22:16       ` Mitch Harder
2011-04-30 22:33         ` John Wyzer
2011-05-03 11:05           ` Chris Mason
2011-05-03 11:06           ` Chris Mason
2011-04-30 23:55     ` Peter Stuge
2011-05-03 10:33       ` Bernhard Schmidt
2011-05-03 11:00         ` cwillu
2011-05-03 11:26           ` Bernhard Schmidt
2011-05-03 11:08         ` Chris Mason
2011-05-03 11:30           ` Bernhard Schmidt
2011-05-03 11:36             ` Chris Mason
2011-05-03 11:43               ` Bernhard Schmidt
2011-05-03 12:52                 ` Chris Mason
2011-05-03 13:03                   ` Bernhard Schmidt
2011-05-03 13:41                     ` Mitch Harder
2011-05-03 14:41                   ` Daniel J Blueman
2011-05-03 15:42                     ` Mitch Harder
2011-05-03 16:51                       ` Chris Mason
2011-05-03 14:54             ` Daniel J Blueman
2011-05-03 15:10               ` Bernhard Schmidt
     [not found]   ` <1304100271-sup-4177@localhost>
     [not found]     ` <1304100862-sup-1493@think>
     [not found]       ` <1304107977-sup-3815@localhost>
     [not found]         ` <1304110058-sup-7292@think>
     [not found]           ` <1304146193-sup-2200@localhost>
2011-04-30 20:51             ` John Wyzer

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