Date: Tue, 28 May 2002 10:50:20 -0600 From: "Jan L. Peterson" <jlp@softhome.net> To: "Phil Rosenthal" <winter@villaweb.net> Cc: freebsd-stable@freebsd.org Subject: Re: Hardware RAID vs vinum Message-ID: <20020528165020.8DC37AC44F@mail.flipdog.com> In-Reply-To: Your message of "Sun, 26 May 2002 23:41:39 EDT." <004701c20530$68e98a20$0700a8c0@zoom> References: <004701c20530$68e98a20$0700a8c0@zoom>
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My experience may be contrary to others. My particular application got much much better performance with software RAID (vinum) than with hardware RAID (HP 3-Si card a.k.a. AMI MegaRAID). The application in question had about 16 Windows boxes accessing an SMB filesystem (Samba on the FBSD box). These clients would be all over the disk, accessing hundreds or thousands of different files at different locations on the filesystem every second. Mostly reading, but some writing as well. I got excellent performance out of the hardware raid with only about three or four clients running, but when all sixteen were pounding on the disk, throughput (measured with iostat/systat) was abysmal. Moving the disks to a Symetrics controller and vinum resulted in at least tripple the performance. I accredited it to the fact that the hardware controller had a small cache (32M) vs. the system main memory (1G), and that the system could better schedule reads and writes as it knew more about where the data was on the various disks. I guess what I'm saying is don't simply assume that hardware RAID is good or bad... it's very dependent on your application. We are very satisfied with the hardware RAID on a different box with different usage patterns. -jan- -- Jan L. Peterson <jlp@softhome.net> To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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