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ChUIMonster
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In the modern HW environment from a performance perspective SAN storage is pretty much always inferior to internal disks. If performance is your goal then it is awfully hard to argue against internal SSD. Which is also probably cheaper. Think about it... SAN storage is external and shared. Both of those facts contribute major obstacles. They only way that SAN can win is to be compared to crippled internal disks. 20 years ago that is in fact how SAN got a leg up. You could not physically put enough internal disks in a server to match the storage capacity or the IO Ops of a SAN. The landscape today has changed. Capacity stopped being a challenge ages ago and SSDs cured the IO Ops problem. Now the latency from server to SAN is a significant chunk of the IO response -- there is an order of magnitude difference in an IO to an internal SSD vs an IO Op to a SAN. If your external storage is also shared then you're in even more trouble. I have had some experience with EMC VNX and it is not an exception. In the last round of testing that I did on one of those when we put all of the data on SSD it was actually *slower*. The speculation was that there was a bottleneck on the SSD controller but we didn't keep digging into it.
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