Re: RAID 5 throughputs

[Justin Piszcz <jpiszcz@lucidpixels.com>]

On Sat, 19 Aug 2006, jassduec@gmail.com wrote:

> Hi All,
>
> I have a storage system with 12 Maxtor 7200 rpm 250GB hard drives in
> RAID 5 configuration with one hot spare. Maxtor claims that each drive
> is capable of providing 56 MB/s sustained throughput. My host system
> is connected to it using 64bit ultra320 Adaptec SCSI card. The host
> system has 3.0 GHz pentium 4 (with HT) processor and 4 GB of RAM
> running linux kernel 2.6.9. I was wondering what order of "maximum"
> sequential read/write, random read/write throughput should i expect
> using them. I am using some of the benchmarking tools like Bonnie,
> Bonnie++, tiobench, dd, iometer etc. However the results from them
> have been very depressing. Theoretically i should be able to achieve a
> read sequential throughput close to min(10*56 = 560, 320) = 320 MB/s.
> However my results are no way close to it. I was wondering if anybody
> can give me some insight of what order of practical throughputs i
> should expect using linux and what other factors may be creating
> bottlenecks.
>
> TIA
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Is your 64bit ultra320 card in a 64bit PCI + 66MHZ slot?

If not, you will be limited to 133mb/s.