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Gents, We have a database server (Oracle), its raid array is read intensive... Raid Controller type:

04:00.0 RAID bus controller: Hewlett-Packard Company Smart Array G6 controllers (rev 01)
07:00.0 RAID bus controller: Hewlett-Packard Company Smart Array G6 controllers (rev 01)

Here are the values we are seeing via iostat:

cciss/c1d0     4933.00    788848.00      7088.00     788848       7088

File system is ext3... Can/should we expect greater performance from this setup?

Anything specific you would recommend I check/do?

Thanks!!!

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closed as not a real question by thinice, Lucas Kauffman, Chopper3, womble, ewwhite Aug 8 '12 at 16:15

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We're missing some of the details. Which server model is this? I'm assuming the controller is a Smart Array P410i, however, the number type and RAID arrangement of the disks would also be helpful. –  ewwhite Aug 1 '12 at 22:03
    
@ewwhite cciss0: HP Smart Array P410i Controller. Logical drives: 2 Raid 1(1+0) –  CMag Aug 1 '12 at 22:10
    
What are the drives? 10k? 15k? –  David Aug 2 '12 at 0:49
    
mmmm, not sure... lets assume 10K –  CMag Aug 2 '12 at 21:54

1 Answer 1

You don't say what controller you have but most G6 servers come with a P410i, which has a PCIe 2.O x8 connector. So that could, at least theoretically, deliver 4GBps Either way, so if we take typical 4k reads and writes, 100% from cache and without overhead you'd be able to read and write that same block ~1m times per second both ways.

Of course this is all entirely theoretical because you won't want to actually do that but then you've only given us maybe 2% of the information we'd actually need to help you but it does answer your question as written.

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Now you've told us some (small) information then even if you've got a pair of 146GB 15krpm disks in that box then ignoring controller and disk caching the most you've get our a R1 (it's not a R10 if you only have 2 disks) will be ~2x180 IOPS, so 360 for random read/write. So if you're seeing nearly 5k IOPS you must be getting a hell of a lot of successful cache hits –  Chopper3 Aug 1 '12 at 22:54
    
Typo sorry, 360 for read, 180 for write. –  Chopper3 Aug 1 '12 at 23:00
    
Thanks!!! So how do you make a correlation between 2x180 and 8000 IOPS :) So what I can read from this is... we are maxing the IOPS on this controller... hardware bottleneck is the answer –  CMag Aug 1 '12 at 23:54
    
where can i get the first number you are saying? The 2x180 IOPS? Is it the cat /proc/driver/cciss/cciss1 ? or somewhere else, or just a known hardware spec –  CMag Aug 1 '12 at 23:55
    
That's the max guarunteed non-cached random read/write capability of those disks, I buy them too. –  Chopper3 Aug 2 '12 at 6:50

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