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From: Dave Chinner <david@fromorbit.com>
To: Linas Jankauskas <linas.j@iv.lt>
Cc: xfs@oss.sgi.com
Subject: Re: Slow performance after ~4.5TB
Date: Mon, 12 Nov 2012 23:32:22 +1100	[thread overview]
Message-ID: <20121112123222.GT24575@dastard> (raw)
In-Reply-To: <50A0C590.6020602@iv.lt>

On Mon, Nov 12, 2012 at 11:46:56AM +0200, Linas Jankauskas wrote:
> 
> Servers are HP dl180 g6
> OS centos 6.3 x86_64
>
> CPU
> 2x Intel(R) Xeon(R) CPU           L5630  @ 2.13GHz
> 
> uname -r
> 2.6.32-279.5.2.el6.x86_64
> 
> xfs_repair -V
> xfs_repair version 3.1.1
> 
> 
> cat /proc/meminfo
> MemTotal:       12187500 kB
> MemFree:          153080 kB
> Buffers:         6400308 kB

That looks strange - 6GB of buffers? That's block device cached
pages, and XFS doesn't use the block device for caching. You don't
have much in the way of ext4 filesystems, either, so i don't thik
that is responsible.

> cat /proc/mounts
> rootfs / rootfs rw 0 0
> proc /proc proc rw,relatime 0 0
> sysfs /sys sysfs rw,relatime 0 0
> devtmpfs /dev devtmpfs
> rw,relatime,size=6084860k,nr_inodes=1521215,mode=755 0 0

A 6GB devtmpfs? That seems unusual. What is the purpose of having a
6GB ramdisk mounting on /dev?  I wonder if that is consuming all
that buffer space....

>       logicaldrive 1 (20.0 TB, RAID 5, OK)
> 
>       physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SATA, 2 TB, OK)
>       physicaldrive 1I:1:2 (port 1I:box 1:bay 2, SATA, 2 TB, OK)
>       physicaldrive 1I:1:3 (port 1I:box 1:bay 3, SATA, 2 TB, OK)
>       physicaldrive 1I:1:4 (port 1I:box 1:bay 4, SATA, 2 TB, OK)
>       physicaldrive 1I:1:5 (port 1I:box 1:bay 5, SATA, 2 TB, OK)
>       physicaldrive 1I:1:6 (port 1I:box 1:bay 6, SATA, 2 TB, OK)
>       physicaldrive 1I:1:7 (port 1I:box 1:bay 7, SATA, 2 TB, OK)
>       physicaldrive 1I:1:8 (port 1I:box 1:bay 8, SATA, 2 TB, OK)
>       physicaldrive 1I:1:9 (port 1I:box 1:bay 9, SATA, 2 TB, OK)
>       physicaldrive 1I:1:10 (port 1I:box 1:bay 10, SATA, 2 TB, OK)
>       physicaldrive 1I:1:11 (port 1I:box 1:bay 11, SATA, 2 TB, OK)
>       physicaldrive 1I:1:12 (port 1I:box 1:bay 12, SATA, 2 TB, OK)

OK, so RAID5, but it doesn't tell me the geometry of it.

> xfs_info /var
> meta-data=/dev/sda5              isize=256    agcount=20,
> agsize=268435455 blks
>          =                       sectsz=512   attr=2
> data     =                       bsize=4096   blocks=5368633873, imaxpct=5
>          =                       sunit=0      swidth=0 blks

And no geometry here, either.

> naming   =version 2              bsize=4096   ascii-ci=0
> log      =internal               bsize=4096   blocks=521728, version=2
>          =                       sectsz=512   sunit=0 blks, lazy-count=1
> realtime =none                   extsz=4096   blocks=0, rtextents=0
> 
> No dmesg errors.
> 
> vmstat 5
> procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
>  1  0   2788 150808 6318232 2475332    0    0   836   185    2    4 1 11 87  1  0
>  1  0   2788 150608 6318232 2475484    0    0     0    89 1094  126 0 12 88  0  0
>  1  0   2788 150500 6318232 2475604    0    0     0    60 1109   99 0 12 88  0  0
>  1  0   2788 150252 6318232 2475720    0    0     0    49 1046   79 0 12 88  0  0
>  1  0   2788 150344 6318232 2475844    0    0     1   157 1046   82 0 12 88  0  0
>  1  0   2788 149972 6318232 2475960    0    0     0   197 1086  144 0 12 88  0  0
>  1  0   2788 150020 6318232 2476088    0    0     0    76 1115   99 0 12 88  0  0
>  1  0   2788 150012 6318232 2476204    0    0     0    81 1131  132 0 12 88  0  0
>  1  0   2788 149624 6318232 2476340    0    0     0    53 1074   95 0 12 88  0  0

basically idle, but burning a CPu in system time.

> iostat -x -d -m 5
> Linux 2.6.32-279.5.2.el6.x86_64 (storage)     11/12/2012
> _x86_64_  (8 CPU)
> 
> Device:         rrqm/s   wrqm/s     r/s     w/s    rMB/s    wMB/s avgrq-sz avgqu-sz   await  svctm  %util
> sda             103.27     1.51   92.43   37.65     6.52     1.44   125.36     0.73    5.60   1.13  14.74
> sda               0.00     0.20    2.40   19.80     0.01     0.09     9.08     0.13    5.79   2.25   5.00
> sda               0.00     3.60    0.60   36.80     0.00     4.15   227.45     0.12    3.21   0.64   2.38
> sda               0.00     0.40    1.20   36.80     0.00     8.01   431.83     0.11    3.00   1.05   4.00
> sda               0.00     0.60    0.00   20.60     0.00     0.08     8.39     0.01    0.69   0.69   1.42
> sda               0.00    38.40    4.20   27.40     0.02     0.27    18.34     0.25    8.06   2.63   8.32

Again, pretty much idle.

So, it's not doing IO, it's not thrashing caches, so what is burning
cpu? Can you take a profile? maybe just run 'perf top' for 15s and
then just paste the top 10 samples?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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  reply	other threads:[~2012-11-12 12:30 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-12  8:14 Slow performance after ~4.5TB Linas Jankauskas
2012-11-12  9:04 ` Dave Chinner
2012-11-12  9:46   ` Linas Jankauskas
2012-11-12 12:32     ` Dave Chinner [this message]
2012-11-12 13:58       ` Linas Jankauskas
2012-11-12 22:36         ` Dave Chinner
2012-11-13  9:13           ` Linas Jankauskas
2012-11-13 19:50             ` Dave Chinner
2012-11-14  9:01               ` Linas Jankauskas
2012-11-14 21:13             ` Dave Chinner
2012-11-15  8:34               ` Linas Jankauskas

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