Date: Fri, 03 Nov 2000 22:02:01 -0600 From: Gabor Kincses <gabor@acm.org> To: randy@psg.com Cc: scsi@freebsd.org Subject: Re: CCD Message-ID: <3A038A39.D646F2F2@acm.org>
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Hello, This is all I had to do: KERNEL config file: pseudo-device ccd 4 # Concatenated disk driver gabor@steinbeck: <1160> cat /etc/ccd.conf ccd0 512 0 /dev/ad0s3f /dev/ad2s1f I have been using this since June. Early on I measured performance and I got ~75% increased random read and sequential block read/write per bonnie. bonnie suffers from file system caching but I ran it with 2x the size of my ram, which should eliminate caching artifacts. BTW, the two disks are quite dissimilar (13 and 4 GB), I just made sure to create identical sized `f' partitions. Since performance speaks for itself, I consider the disk geometry a non-issue. Granted I had to increase the interleave factor to much bigger than what the man page recommended to get optimum performance. You may also want to strip swap like this (/etc/fstab): /dev/ad0s2b none swap sw 0 0 /dev/ad2s1b none swap sw 0 0 I may have had to fiddle with disklabel when installing, but it wasn't a big deal, I think I just followed ccdconfig(8). BTW, does anybody have numbers on IDE disk speeds to help decide if a third disk would max-out a 33MHz UDMA IDE controller? -- Gabor Kincses (gabor@acm.org) Running FreeBSD 4.0-STABLE To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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