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Hello all; I run an 8 x 1TB[7.2k] RAID10 system running Xen. I disabled all Xen VMs and have gotten this as a result. /dev/cciss/c0d1: Timing cached reads: 19412 MB ...
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  1. #1
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    Hardware RAID10 Performance


    Hello all;

    I run an 8 x 1TB[7.2k] RAID10 system running Xen. I disabled all Xen VMs and have gotten this as a result.


    /dev/cciss/c0d1:
    Timing cached reads: 19412 MB in 1.99 seconds = 9759.28 MB/sec
    HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate ioctl for device
    Timing buffered disk reads: 250 MB in 3.00 seconds = 83.30 MB/sec
    HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate ioctl for device


    The cached reads vary from 9.5k-12k whereas the buffered reads vary from 80-150.

    Are the buffered reads too slow?

  2. #2
    Linux Guru Rubberman's Avatar
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    The cached reads (almost 10GB/sec) is coming from memory. The buffered reads (~700mbps) are coming off the disc, and that isn't too shabby. Is that 80-150 bytes per read, or 80-150KB per read?
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

  3. #3
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    The cached reads are fine. I am basing the 80-150MB/S off the average I've seen. I believe those are megabytes. But I have seen raid10 users get up to 400 MB/S

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    If they are 80-150KB then yes I think there is an issue. they should be in MB what I think.

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