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How do you calculate your maximum throughput available for a RAID volume? Do you use your VMFS block size per IOP? Your OS Blocksize? Your array stripe size? Any idea?

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up vote 1 down vote accepted

The OS\App blocksize and your IO patterns are what you want to focus on.

VMFS blocksize has no effect on IO patterns - it affects the maximum file size that a particular VMFS can contain not the read\write IO size. Array strip size has an effect but it's more indirect and the optimal stripe size depends on the IO patterns and the storage system you are using - in general go with the vendors recommendation for your workload or the default unless you have benchmarks that tell you otherwise.

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What I always do is to benchmark the array by booting one of the hosts into linux, format the LUN using ext2 and just using iozone - it's close enough.

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