"Steinmetz, Paul" <PSteinmetz@xxxxxxxxxx> wrote on Tue, 26 Aug
2014 15:13:15 GMT:

Why would you pick a backplane option with 0 write cache.

If the workload is not sensitive to write response time, write
cache is not a factor. If you utilize SSDs, even with a 2ms
average write response time, the lack of write cache may not be
a factor for the workload.

History has proven that the CEC with 0 write cache will be a
performance issue.

The adapters in the POWER7 and earlier CECs had limited IOPS and
MB/s throughput capabilities. In many cases, these limitations
and not the lack of write cache was the real culprit for poor

History also has shown that the CEC should
be avoided for a production lpar.

I will agree for POWER7 and earlier systems. I will disagree
for the POWER8 S814 and S824 models with high function
backplane. The on-board disk IOAs are better than the feature
ESA3 and 5913 adapters used by many on POWER7 for write
intensive and write response time sensitive workloads.

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