Scott Carey wrote: > On 10/5/09 11:15 AM, "Karl Denninger" <k...@denninger.net> wrote: > > >> I'm running the 9650s in most of my "busier" machines. Haven't tried a >> PERC card yet - its on my list. Most of my stuff is configured as RAID >> 1 although I have a couple of RAID 10 arrays in service; depending on >> the data set and how it splits up I prefer to have more control of how >> I/O is partitioned rather than let the controller pick through striping. >> >> I don't think I have any of the 95xx stuff out in the wild at present; >> it didn't do particularly well in my testing in terms of performance. >> >> -- Karl >> > Let me make sure I clarify here -- > > The 3ware 9[56]xx issues I have seen were with throughput on larger RAID > array sizes -- 8+ disks total. On smaller arrays, I have not tested. > > Interesting... I'm curious if that's why I haven't run into it - I get damn close to N x rotational on sequential I/O out of these boards; you can't really do better than the physics allow :)
I'll have to play with some larger (> 8 unit) Raid 1 and Raid 10 arrays and compare to see if there's a "knee" point and whether its a function of the aggregation through the chipset or whether it's a card issue. I suspect it's related to the aggregation as otherwise I'd have seen it on some of my larger configurations, but I tend to run multiple adapters for anything more than 8 spindles, which precludes the situation you've seen. Of course if you NEED 12 spindles in one logical device for capacity reasons........ -- Karl
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