Re: xfs_fsr, sunit, and swidth

Dave Hall
2013-03-14T14:59:32Z

[-- Attachment #1.1: Type: text/plain, Size: 4497 bytes --]

Dave Hall
Binghamton University
kdhall@binghamton.edu
607-760-2328 (Cell)
607-777-4641 (Office)

On 03/14/2013 08:55 AM, Stan Hoeppner wrote:
>> Yes, please provide the output of the following commands:
>>
> ~$ uname -a
>
Linux decoy 3.2.0-0.bpo.4-amd64 #1 SMP Debian 3.2.35-2~bpo60+1 x86_64
GNU/Linux
>> > ~$ grep xfs /etc/fstab
>>
LABEL=backup /infortrend xfs
inode64,noatime,nodiratime,nobarrier 0 0
(cat /proc/mounts: /dev/sdb1 /infortrend xfs
rw,noatime,nodiratime,attr2,delaylog,nobarrier,inode64,noquota 0 0)

Note that there is also a second XFS on a separate 3ware raid card, but
the I/O traffic on that one is fairly low. It is used as a staging area
for a Debian mirror that is hosted on another server.
>> > ~$ xfs_info/dev/[mount-point]
>>
# xfs_info /dev/sdb1
meta-data=/dev/sdb1 isize=256 agcount=26,
agsize=268435455 blks
= sectsz=512 attr=2
data = bsize=4096 blocks=6836364800, imaxpct=5
= sunit=0 swidth=0 blks
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
>> > ~$ df/dev/[mount_point]
>>
# df /dev/sdb1
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sdb1 27343372288 20432618356 6910753932 75% /infortrend
>> > ~$ df -i/dev/[mount_point]
>>
# df -i /dev/sdb1
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/sdb1 5469091840 1367746380 4101345460 26% /infortrend
>> > ~$ xfs_db -r -c freesp/dev/[mount-point]
>>
# xfs_db -r -c freesp /dev/sdb1
from to extents blocks pct
1 1 832735 832735 0.05
2 3 432183 1037663 0.06
4 7 365573 1903965 0.11
8 15 352402 3891608 0.23
16 31 332762 7460486 0.43
32 63 300571 13597941 0.79
64 127 233778 20900655 1.21
128 255 152003 27448751 1.59
256 511 112673 40941665 2.37
512 1023 82262 59331126 3.43
1024 2047 53238 76543454 4.43
2048 4095 34092 97842752 5.66
4096 8191 22743 129915842 7.52
8192 16383 14453 162422155 9.40
16384 32767 8501 190601554 11.03
32768 65535 4695 210822119 12.20
65536 131071 2615 234787546 13.59
131072 262143 1354 237684818 13.76
262144 524287 470 160228724 9.27
524288 1048575 74 47384798 2.74
1048576 2097151 1 2097122 0.12
>> >
>> > Also please provide the make/model of the RAID controller, the write
>> > cache size and if it is indeed enabled and working, as well as any
>> > errors, if any, logged by the controller in dmesg or elsewhere in Linux,
>> > or in the controller firmware.
>> >
>>
The RAID box is an Infortrend S16S-G1030 with 512MB cache and a fully
functional battery. I couldn't find any details about the internal
RAID implementation used by Infortrend. The array is SAS attached to
an LSI HBA (SAS2008 PCI-Express Fusion-MPT SAS-2).

The system hardware is a SuperMicro quad 8-core XEON E7-4820 2.0GHz with
128 GB of ram, hyper-theading enabled. (This is something that I
inherited. There is no doubt that it is overkill.)
>>> >>
Another bit of information that you didn't ask about is the I/O
scheduler algorithm. I just checked and found it set to 'cfq', although
I though I had set it to 'noop' via a kernel parameter in GRUB.

Also, some observations about the cp -al: In parallel to investigating
hardware/OS/filesystem issue I have done some experiments with cp -al.
It hurts to have 64 cores available and see cp -al running the wheels
off just one, with a couple others slightly active with system level
duties. So I tried some experiments where I copied smaller segments of
the file tree in parallel (using make -j). I haven't had the chance to
fully play this out, but these parallel cp invocations completed very
quickly. So it would appear that the cp command itself may bog down
with such a large file tree. I haven't had a chance to tear apart the
source code or do any profiling to see if there are any obvious problems
there.

Lastly, I will mention that I see almost 0% wa when watching top.

[-- Attachment #1.2: Type: text/html, Size: 9926 bytes --]

[-- Attachment #2: Type: text/plain, Size: 121 bytes --]