Subject: Re: RAID: which level to use? (documentation slightly lacking)
To: None <>
From: Greg Oster <>
List: tech-kern
Date: 04/22/1999 16:13:15
Thor Lancelot Simon writes:
> But something is terribly wrong with RAIDframe's mirroring code.  Its
> striping (RAID 0) code is only about 5-10% slower than our old 'ccd'
> device, but a mirror of two 7200RPM SCSI disks for me writes only at about
> 20-40KB/sec!  I don't consider that useful.

Wowzers!!! That's brutal!!  Can you send me (privately) a copy of your
RAID config files, dmesg, and anything else you might think is relevant?
(e.g. how you measured the 20-40KB/sec.)

I just whipped up a RAID1 on my test box (A P133 w/ 32MB of RAM, using a 
pair of 1GB IBM 0662S12's on a single FastNarrow NCR SCSI controller in 
this case) and Bonnie gives me:

              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
rizzo     500  1565 47.7  2217  8.3  1217  8.0  2564 85.9  2933 10.2  43.5  6.1

There's no way my junky 3MB/sec 1GB SCSI drives should be outperforming
decent 7200RPM SCSI drives.... :-(



Greg Oster