On 1/21/07, Liang Yang <[EMAIL PROTECTED]> wrote:
Hello,
I have tried to increase the Striped_Cache_Size from 256 (default for my
MD-RAID5 array) to 8192, it does improve the MD-RAID5 Write performance
which varies with the size of I/O packet.
However, I'm still not very clean the meaning and the potential performance
impact of this Striped_Cache_Size? Is the unit for this parameter Byte or
KiloByte?
Could anyone here explain with a little bit more details?
stripe_cache_size is the number of stripes in the cache. Each stripe
(strip) is composed one PAGE_SIZE block per disk. If your page size
is 4k and you have 4 disks in your array then a stripe_cache_size of
256 is 4k * 4 * 256 = 4MB.
Increasing this number increases the chances that a write to the array
will not generate reads to satisfy the parity calculation.
Thanks,
Liang
Regards,
Dan
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