Le Sat, 30 Apr 2011 14:54:02 -0500 vous Ãcriviez:
> Just having write back cache isn't magic by itself. The cache
> management algorithm and configuration thereof are often as
> important, if not more, than the total cache size on the RAID HBA or
> SAN controller.
>
> Poor cache management, I'd guess, is one reason why you see Areca
> RAID cards with 1-4GB cache DRAM whereas competing cards w/ similar
> price/performance/features from LSI, Adaptec, and others sport 512MB.
Yes, probably. To give some meat to the argument :
Using XFS mounted nobarrier on an 8 drives RAID-6 array with WB cache :
30000 journal (file creation/deletion) operations/s
Using XFS with barriers on the same RAID : 7000 journal operations/s
Using XFS nobarrier with WT cache : 700 journal op/s.
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Emmanuel Florac | Direction technique
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