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CX4-240 disk performance

Hi all,

I am wondering if someone could confirm or speculate regarding some performance figures we are seeing from a CX4-240.

The figures seem too slow. We would like to get a feel for other experiences if possible.

Setup overview:

Blades: RHEL5 AMD Opteron, 8GB RAM, 2x 15K SAS mirror, 2x QLogic 4Gb FC HBAs

2x Brocade 5000 FC Switches

Flare 04.29

15x 400GB 10K FC disks

15x 1TB 7.2K SATA disks

HBA's & switches at minimal workload.

Test LUNs on separate SPs (normal, not metaLUNs or Thin LUNs)

Caching disabled on Test LUNs.
Ext3 filesystems on both LUNs.

LUNs & Blade OS idle when tests were performed.

Tests performed on separate blades to confirm results.


LUN2, 10x FC RAID5

Sequential r/w, LUN1 -> LUN1: avg 13MB/s

Sequential r/w, LUN2 -> LUN2: avg 27MB/s

Sequential r/w, LUN1 -> LUN2: avg 15MB/s

Sequential r/w, LUN2 -> LUN1: avg 17MB/s

Sequential r/w, Host SAS -> LUN1: avg 16MB/s

Sequential r/w, LUN1 -> Host SAS: avg 17MB/s

Sequential r/w, Host SAS -> LUN2: avg 60MB/s

Sequential r/w, LUN2 -> Host SAS: avg 82MB/s

Any comments would be most welcome.

We are in the process of running more tests (random workload, different size RAIDs)

Best Regards,

Logan Cale

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1 Reply
4 Tellurium

Re: CX4-240 disk performance

Hi Logan,

I have same situation.

I have checked iowait using sysstat utility on RHEL, I have discovery many value than non EMC system.

And I have checked que value on powermt utility, I have discovery many queing value.

Then I have tried to single path access, SPA-0 to a HBA port.

This access performance is very well, minimum iowait and minimum queing.

I think so PowerPath for Linux has any bugs or I need any special settings???

If you can test, please check sysstat-iowait and powermt-que value

with multi-path and single-path environment.

Best Regards.

Nori Ishitsuka

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