external raid arrays

[Tim Carlson]

On Thu, 21 Feb 2002, Velocet wrote:

> We get 54Mb/s read and 44Mb/s write with raid 0+1 on 10Krpm IBM LVD 160
> drives with 1 controller. I would expect, with suitably fast CPUs (ours
> is a Tbird 900) and 66/64 pci slots with some nice Tekram (we swear by
> these) or Adaptec controllers that 4 of them with 12 10Krpm drives would
> probably easily net you over 100MB/s read and write.

Here are bonnie numbers on a Dell 530 Dual 1.7Ghz box with an Adaptec
39160 card using both channels to a Dell PowerVault array filled with 8
36Gig U160 drives. This is a flat raid 0. Basically, it is fast as hell
:). You can't get this fast with hardware raid under Linux. For hardware
raid, the Dell Perc3 cards (Megaraid based) give poor performace. The
Adaptec 3210S outperforms the Perc3 by a fair amount, but software raid
beats them all hands down.

Version 1.01d       ------Sequential Output------ --Sequential Input-
--Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
              6240M 19900  99 214098  68 88136  38 19648  97 229752  51 372.4
                    ------Sequential Create------ --------Random Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16  2745 100 +++++ +++ +++++ +++  2817 100 +++++ +++  5922  99


Tim Carlson
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Email: Tim.Carlson at pnl.gov
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