RAID10 not working in install
Bill Davidsen
davidsen at tmr.com
Mon Feb 25 20:54:43 UTC 2008
Alan Cox wrote:
>> The raw read speed on a RAID1 array is the speed of a single drive. The
>>
>
> No. A smart raid1 driver will use both source disks. The raw write speed
> is that of the slowest drive (plus overhead).
>
>
Does this mean that the Linux software RAID is not smart, or there's a
way to make it actually do this? Current FC[678] doesn't seem to be
"smart."
> RAID 10 gives you better write throughput which on a modern PC normally
> means that with PCI Express your bridge/memory bandwidth becomes the
> limit.
>
>
This is what I measure running an E6600 CPU and 3xSeagate 320 with
Recent FC7 kernel. All reads and writes to the raw array using dd, 1MB
buffer, 1GB i/o to/from /dev/{zero,null} for raw speed. Units are MB/s,
64k chunks, speed as reported by dd.
RAID lvl read write
0 110 143
1 52.1 49.5
10 79.6 76.3
10f2 145 64.5
raw one disk 53.5 54.7
> Alan
>
>
--
Bill Davidsen <davidsen at tmr.com>
"Woe unto the statesman who makes war without a reason that will still
be valid when the war is over..." Otto von Bismark
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