write performance on global mounted se6920 ufs
Hi,
We抳e a 3-node e2900 cluster with se6920 storage into production primarily as a database server.
The database is performing as fast as we expected and no complaints there, however we are noticing some behaviour on the globally mounted ufs partitions that we did not expect to see?br>
Writing log files to the global storage is much slower by comparison to writing log files locally on the system disk. We do open and close the log file each time so I guess there has to be some read going on each time?and the log files can grow up to 20mb.
Maybe this is not so strange? It could be that we just have tuned the se6920 for our Sybase application to the detriment of this type of I/O?br>
SE6920 profile properties:
Profile:
Description:
RAID Level:1
Segment Size: 64KB
Read Ahead:off
Optimal Number of Drives: variable
Array Type:Best Available Match IOPS
Virtualization Strategy:concatenate
Dedicated Hot Spare:no
Profile in Use:yes
Factory Profile:no
Unfortunately, apart from running a few iostat commands and comparing the times it takes to write log files to local and global ufs?I抦 not too sure how I can determine if there is some configuration issue here.
Does anybody know if there is some way to verify what is happening on the se6920 ufs partitions? - there is no measurable differences for cp files ranging from 10mb to 2 gb between the local and global partitions.
Here are some iostat results for writing a 500k log file (opening/closing for each line appended):
Local (svm d40):
Time: 32s
Sample iostat:
r/sw/skr/skw/s wait actv wsvc_t asvc_t %w %b device
0.0 273.00.0 4366.4 0.2 60.80.6 222.7 15 98 d40
0.0 377.40.0 6035.0 0.0 2.00.05.40 77 d40
0.0 421.20.0 6701.1 0.0 2.20.05.21 69 d40
0.0 292.20.0 4036.7 0.1 135.10.4 462.2 13 94 d40
0.2 253.81.6 3152.1 0.6 426.32.3 1678.2 57 100 d40
0.0 277.60.0 4011.7 0.4 102.61.6 369.6 43 100 d40
0.0 178.00.0 1592.0 0.1 210.80.3 1184.45 99 d40
0.037.40.0 299.2 0.0 17.00.0 455.80 32 d40
Global (c5t600015D000042D00000000000000110Dd0) :
Time: Had to stop the logging application ?had only completed 43k lines in 17mins
Sample iostat:
r/sw/skr/skw/s wait actv wsvc_t asvc_t %w %b device
0.010.60.028.4 0.0 0.00.01.802 c5t600015D000042D00000000000000110Dd0
0.012.20.056.6 0.0 0.00.01.502 c5t600015D000042D00000000000000110Dd0
2.810.49.440.1 0.0 0.00.01.402 c5t600015D000042D00000000000000110Dd0
3.022.212.4 100.0 0.0 0.00.01.704 c5t600015D000042D00000000000000110Dd0
2.610.810.033.5 0.0 0.00.01.202 c5t600015D000042D00000000000000110Dd0
2.614.210.271.2 0.0 0.00.01.702 c5t600015D000042D00000000000000110Dd0
3.018.212.266.3 0.0 0.00.01.303 c5t600015D000042D00000000000000110Dd0
3.018.412.666.5 0.0 0.00.02.004 c5t600015D000042D00000000000000110Dd0
0.615.43.241.3 0.0 0.00.02.103 c5t600015D000042D00000000000000110Dd0
0.017.60.0 124.0 0.0 0.10.03.606 c5t600015D000042D00000000000000110Dd0
0.27.21.216.4 0.0 0.00.02.001 c5t600015D000042D00000000000000110Dd0
0.014.80.046.8 0.0 0.00.01.803 c5t600015D000042D00000000000000110Dd0
0.424.02.084.1 0.0 0.00.01.703 c5t600015D000042D00000000000000110Dd0
0.419.41.869.5 0.0 0.00.01.503 c5t600015D000042D00000000000000110Dd0
Thanks for your time!
Trevor
