October 16, 2014 at 7:43 pm
Hi guys,
My SQL server ETL has been running slow lately, so I ran a bunch of CrystalDiskMark and SQLIO bench mark on my SAN to gauge whether it's disk / hardware related, or what not.
I understand CrystalDiskMark may not be the best test for SQL performance in general... but I am only getting 0.7MB/s for 4k random read on my SAN .. which regardless of whether it's a good test or not, it still sounds low.... I am wondering if this is normal or not.
What's a normal 4k random read performance for a normal SAN (based on hybrid ssd + hdd technologies)???
January 23, 2015 at 5:08 pm
I know this is an old post. I can't help but wonder why there has been no response. It's a good question, which is why I'm here. I don't expect performance from a SAN to match local storage. Some metrics will be good, but others often fall short. The random 4K is often one of them. Anyway, I do a lot better than .75 MB/sec on 4K writes. I get whopping 1.2 to 3 MB/sec, depending upon which drive I test. To compare, I tested a physical mirror with slow drives with a result of 4.5 MB/sec.
I figure there is some sort of throttle between the virtual disk and the SAN. This load is nothing to the new SAN. However, there are a lot of VMs and drives on the SAN, so perhaps the total load is taking a toll. However, any crappy drive can provide more than 200-300 IOPs at 4K.
RandyHelpdesk: Perhaps Im not the only one that does not know what you are doing. 😉
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