Date: Tue, 19 Oct 2004 14:21:14 -0500 From: Kristofer Pettijohn <krishopper@cybernetik.net> To: freebsd-questions@freebsd.org Subject: Disk I/O Perforamnce with CCD Message-ID: <20041019192114.GA78974@cybernetik.net>
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Im looking for some suggestions on I/O performance. I'm using FreeBSD 4.10-RELEASE on a Usenet transit server running Diablo for the transit software. I have 4 Seagate ST373435LC SCSI drives, 70GB each, and I am using CCD to bind them together with RAID-0 stripes. I can pull in anywhere from 30-40 MB sec and push out ~ 8-15 MB/sec.. averaging about 50 MB/sec throughput.. feeds coming in are coming in just fine, but sending stuff back out is lagging behind.. its falling about a half hour behind every hour. I've used tunefs to set the average file size to 20 MB and enabled soft-updates, as these are generally larger binary files that just get appended to, and then seeked later on to send the article out, I've played with setting the stripe size from anywhere between 8MB and 64MB, and did not see much change on performance between those. Maybe I'm just missing something small, but on these SCSI drives which have 160 MB/s transfer rates, I'm expecting a bit more than I'm getting with CCD. Can someone give me any pointers to look at or suggestions of things to try? Thanks! Kristofer
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