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<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">I believe the older kernels handle the extra cores rather poorly, and don't<br>even recognize the intel CPUs as NUMA enabled. You didn't mention hardware or<br>
software RAID. I'd recommend RAID scrubbing, and if software that requires (I<br>think) >= 2.6.21, although (I think) Redhat back ported it into their newest<br>kernels in 5.4, or maybe 5.3. Definitely not in 5.1 though.<br>
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<div>For performance reasons we added the 3ware card to handle the raid.</div>
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<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">I've not seen a particularly big difference on random workloads typical of<br>databases. Are the databases bigger than ram? Does your 3ware have a<br>
battery? Allowing the raid controller to acknowledge writes before they hit<br>the disk might be a big win (if your DB has lots of writes)? Can you afford a<br>SSD to hold the berkeley DB?<br></blockquote>
<div>The card has 512 MB of memory. I suppose it will cache the writes there. But the bdb's can be up to 70 GB large so we'll never be able to pull them in memory.</div>
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