How much many write can a NC 960 process

Question

There is an EMC NC 960 SAN to which a Unix server is attached.  The SAN performance seems to be poor to be but the SAN administrator says that it is running as it should.  Below is an output of iostat from the Unix server please let me know what you think. The system is showing 4.61% waiting for disk i/o when 9,909 blocks are written. Linux 2.6.18-164.el5PAE (d9v21pimdb1)   03/21/2012 avg-cpu:  %user   %nice %system %iowait  %steal   %idle            1.26    0.00    1.96    4.61    0.00   92.17 Device tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn sda           1.98     0.00     0.00      0      0 sda1          0.00     0.00     0.00      0      0 sda2          0.00     0.00     0.00      0      0 sda3          0.00     0.00     0.00      0      0 sda4          0.00     0.00     0.00      0      0 sda5          1.98     0.00     0.00      0      0 sdb           0.00     0.00     0.00      0      0 sdb1          0.00     0.00     0.00      0      0 sdb2          0.00     0.00     0.00      0      0 sdc           0.00     0.00     0.00      0      0 sdc1          0.00     0.00     0.00      0      0 sdd           0.00     0.00     0.00      0      0 sdd1          0.00     0.00     0.00      0      0 sdd2          0.00     0.00     0.00      0      0 sde           0.00     0.00     0.00      0      0 sde1          0.00     0.00     0.00      0      0 sdf           0.00     0.00     0.00      0      0 sdf1          0.00     0.00     0.00      0      0 sdf2          0.00     0.00     0.00      0      0 sdg           0.00     0.00     0.00      0      0 sdg1          0.00     0.00     0.00      0      0 sdh           0.00     0.00     0.00      0      0 sdh1          0.00     0.00     0.00      0      0 sdh2          0.00     0.00     0.00      0      0 sdi           0.00     0.00     0.00      0      0 sdi1          0.00     0.00     0.00      0      0 dm-0          0.00     0.00     0.00      0      0 dm-1          0.00     0.00     0.00      0      0 dm-2          0.00     0.00     0.00      0      0 dm-3          8.91     0.00    71.29      0     72 dm-4          0.00     0.00     0.00      0      0 dm-5          0.00     0.00     0.00      0      0 dm-6          0.00     0.00     0.00      0      0 dm-7          0.00     0.00     0.00      0      0 dm-8          0.00     0.00     0.00      0      0 dm-9          0.00     0.00     0.00      0      0 dm-10         0.00     0.00     0.00      0      0 emcpowera   248.51     0.00  2035.64      0   2056 emcpowera1    0.00     0.00     0.00      0      0 emcpowera2  248.51     0.00  2035.64      0   2056 emcpowerb   720.79     0.00  7786.14      0   7864 emcpowerb1     720.79    0.00      7786.14      0         7864 dm-11      1238.61     0.00  9908.91      0  10008

afp92Tq1w012558 · Answer

Hi , Can you please let me know if you are facing performace issue on the celerra ? Thanks Vanitha

Paul_v1 · Answer

Yes,

There is a Cloverleaft interface engine connected to the SAN and it is not able to process messages as fast as it should.

When I looked at the performance of the server I noticed the large waiting for disk I/O. For other servers on SANs by other vendors this amount of data is not a problem, but it seems to be on this EMC SAN.

I have seen this type of problem happen on others SANs and it was due to degraded performance because of cache batteries that had expired.

My SAN resource has said this can't be the case for the NC960 as it does not have cache batteries. The battery is for the entire SAN.

Celerra

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