> Date: Wed, 6 Oct 1999 14:03:11 -0400 (EDT)
> From: [EMAIL PROTECTED]
> To: Kenneth Cornetet <[EMAIL PROTECTED]>
> Cc: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>
> Subject: Re: FW: Dream RAID System
>
> On Wed, 6 Oct 1999, Kenneth Cornetet wrote:
> > Hardware RAID does not necessarily preclude speed. I put a Mylex extremeraid
> > 1164 (32MB cache, 2 channels) in a dual 450MHz P3 connected to 4 18GB 10K
> > RPM seagate wide low voltage differential SCSI disks in a raid 5 config and
> > got about 22 MB/sec reads and writes as reported by bonnie.
>
> Were you really getting 22MB/s writes (just as fast as reads)? Was the
> bonnie test size at least 2x physical memory? Those are encouraging
> numbers. I'm looking at building a big file server using more drives and
> an extremeraid. I was worried about write performance and wondering if
> I'd have to do RAID10 rather than RAID5.
File './Bonnie.1103', size: 1073741824
Writing with putc()...done
Rewriting...done
Writing intelligently...done
Reading with getc()...done
Reading intelligently...done
Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done...
-------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
fenris 1024 15716 96.7 45169 70.2 17574 45.8 18524 71.5 47481 38.5 509.5 13.2
System is a dual Xeon 500/1mb w/ 512MB main memory. It has 3
SCSI busses, one UltraWide (DLT tape), and 2 Ultra2 LVD units (one
used, one for expansion). There are 7 seagate 18.2G cheeta drives
installed, the last 6 are a 0 spare RAID5 array running left-symmetric
parity and a chunk of 128. The filesystem was created as follows.
mke2fs -b 4096 -i 16384 -R stride=32 -s sparse-super-flag /dev/md0
tune2fs -c 1 -i 1d -m 10 /dev/md0
e2fsck -yf /dev/md0
As you can see, the read vs write performance is close, not
exact but close. Of course this is software RAID5 on a high end box
(that was serving as a samba disk/printer server for several hundred
stations and 15 printers, and squid proxy for the stations during the
test). Why was it I was looking at hardware RAID again?
15.3MB/sec Char Write
18.0MB/sec Char Read
44.1MB/sec Block Write
46.3MB/sec Block Read
17.1MB/sec ReWrite
---
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