At 04:36 PM 2/22/2001 +0000, Corin Hartland-Swann wrote:
>RAID-10 arrays also give much better read/write/seek performance than the
>RAID-5 array. If you need a larger and/or faster array, you can also use
>eight disks in RAID-10. I'd recommend the 3Ware Escalade 4 or 8-port UDMA
>controllers, with a bunch of standard UDMA disks.
Speaking of RAID-10, I have a question. I've seen hardware RAID-10
implementations that do 4x READ, 2x WRITE with 4 hdds. For Example,
raid1_array1
raid0_array1
+ hda1
+ hda2
raid0_array2
+ hda3
+ hda4
In this example, some RAID-10 implementations would give theoretical 2x
read and 2x write performance by strickly accessing only the blocks in
their array. (This used to be Linux's behavior if I'm not mistaken). But
a smart RAID-10 would be able to increase READ performance to theoretical
4x by reading blocks outside of it's array, because it could read alternate
blocks from all 4 disks for any given I/O (since the same data is on all 4
disks, why not read it?).
So does RAID-10 on Linux utilize every disk for reads in RAID-10, or just
half the disks? (This is probably akin to: does linux-2.4 have a raid10.o
module yet?)
Thanks,
Dan Browning, Cyclone Computer Systems, [EMAIL PROTECTED]
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