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Should SAN or local SAS be faster?

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So I am getting a little bit fast performance out of my locally attached SAS vs my high-end FC SAN storage. Both are 10k disks and configured in RAID5. The SAN has more spindles though. Is this normal? I always kinda thought SAN should blow everything else away. I am not getting bad performance out of either, just my benchmarks are about 25% better on the local SAS.

Local is a 4 x 146GB SAS connected to an HP p400/512 controller

SAN is a IBM DS8100 with 14x146GB SAS with 4gb FC.

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Depends on the kind of IO really. A 100MB file is probably going to move around faster on the local SAS disks then on the massive RAID 5 group of 14 disks.

But a 35GB file would probably scream on the SAN in comparison.

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Depends on the kind of IO really. A 100MB file is probably going to move around faster on the local SAS disks then on the massive RAID 5 group of 14 disks.

But a 35GB file would probably scream on the SAN in comparison.

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I didn't think about that, I'm pretty new to the storage world. I ran a test to compare file size performance

When I use a 100MB test file, my local SAS is about 50% faster for random reads!!

When I use a 1GB test file, my SAN is 1000% faster for random reads (in IOs/Sec)!!

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Virtuoso
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I bet your san has a couple gig cache and your local box might not, so you're seeing the cache drop-off going from 100M to 1G.

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Okay, so when we get outside of cache limits, I am getting about 3 times faster on my SAN than on the local disk. That sounds about like what I would expect. Thanks for the hints on proper benchmarking.

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