Hi Dave,
On Freitag, 20. März 2015 10:18:54 Dave Chinner wrote:
> On Thu, Mar 19, 2015 at 06:01:50PM +0100, Hans-Peter Jansen wrote:
> > ~# LANG=C xfs_info /dev/sdc1
> > meta-data=/dev/sdc1 isize=256 agcount=17, agsize=183105406
> > blks
> >
> > = sectsz=512 attr=2, projid32bit=0
> > = crc=0 finobt=0
> >
> > data = bsize=4096 blocks=2929687287, imaxpct=5
> >
> > = sunit=0 swidth=0 blks
> >
> > naming =version 2 bsize=4096 ascii-ci=0 ftype=0
> > log =Intern bsize=4096 blocks=32768, version=2
> >
> > = sectsz=512 sunit=0 blks, lazy-count=1
> >
> > realtime =none extsz=4096 blocks=0, rtextents=0
>
> ....
>
> > ~# LANG=C dd if=Django_Unchained.mp4 of=/dev/null bs=1M
> > 1305+1 records in
> > 1305+1 records out
> > 1369162196 bytes (1.4 GB) copied, 3.32714 s, 412 MB/s
> >
> > Write performance is disastrous: it's about 1.5 MB/s.
> >
> > ~# LANG=C dd if=Django_Unchained.mp4 of=xxx bs=1M
> > 482+0 records in
> > 482+0 records out
> > 505413632 bytes (505 MB) copied, 368.816 s, 1.4 MB/s
>
> Why did it stop half way through? ENOSPC?
Signaled with USR1 (impatient operator..)
> > 1083+0 records in
> > 1083+0 records out
> > 1135607808 bytes (1.1 GB) copied, 840.072 s, 1.4 MB/s
>
> That's incomplete, too.
Still impatient.. Sorry for not omitting superfluous output.
> > The question is, what could explain these numbers. Bad alignment? Bad
> > stripe size? And what can I do to resolve this - without loosing all my
> > data..
> More than likely you've fragmented free space, and so writes
> are small random write IO. Output of 'df -h' and:
>
> $ xfs_db -r -c "freesp -s" <dev>
>
> would be instructive.
With pleasure. In fact, I have two very similar sets:
Filesystem Size Used Avail Use% Mounted on
/dev/sdc1 11T 8.7T 2.3T 80% /work
/dev/sdd1 11T 4.4T 6.6T 40% /video
~# xfs_db -r -c "freesp -s" /dev/sdc1
from to extents blocks pct
1 1 19465 19465 0.00
2 3 27313 67348 0.01
4 7 51150 280764 0.05
8 15 210606 2722553 0.45
16 31 2730 61134 0.01
32 63 3396 152440 0.03
64 127 3012 271804 0.04
128 255 3083 570011 0.09
256 511 3108 1134725 0.19
512 1023 3257 2354022 0.39
1024 2047 3449 4985593 0.82
2048 4095 3427 9820314 1.61
4096 8191 2624 15074450 2.47
8192 16383 1546 17345180 2.85
16384 32767 537 11970907 1.97
32768 65535 216 10151639 1.67
65536 131071 68 5782598 0.95
131072 262143 25 4753893 0.78
262144 524287 40 15117520 2.48
524288 1048575 32 23913842 3.93
1048576 2097151 7 10855214 1.78
2097152 4194303 3 8824217 1.45
8388608 16777215 1 8572687 1.41
67108864 134217727 4 310678786 51.01
134217728 183105406 1 143607762 23.58
total free extents 339100
total free blocks 609088868
average free extent size 1796.19
~# xfs_db -r -c "freesp -s" /dev/sdd1
from to extents blocks pct
1 1 933 933 0.00
2 3 616 1400 0.00
4 7 286 1503 0.00
8 15 549 7084 0.00
16 31 480 12151 0.00
32 63 583 25882 0.00
64 127 463 41568 0.00
128 255 320 57243 0.00
256 511 368 135099 0.01
512 1023 258 180464 0.01
1024 2047 512 800351 0.05
2048 4095 1124 3455641 0.20
4096 8191 1387 8176955 0.46
8192 16383 1422 16262072 0.92
16384 32767 920 21547937 1.22
32768 65535 646 29770655 1.69
65536 131071 971 108167644 6.13
131072 262143 7 1378026 0.08
262144 524287 3 1238114 0.07
524288 1048575 1 655157 0.04
4194304 8388607 1 6882208 0.39
134217728 268435455 6 1566631060 88.74
total free extents 11856
total free blocks 1765429147
average free extent size 148906
Both suffer from the same abysmal write performance.
I took care of testing the idle one (sdd).
Thanks,
Pete
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