Date: Wed, 8 Nov 2000 16:58:30 -0800 From: Alfred Perlstein <bright@wintelcom.net> To: Brian Behlendorf <brian@collab.net> Cc: stable@FreeBSD.ORG Subject: Re: disk I/O Message-ID: <20001108165829.F5112@fw.wintelcom.net> In-Reply-To: <Pine.BSF.4.21.0011081625011.1844-100000@yez.hyperreal.org>; from brian@collab.net on Wed, Nov 08, 2000 at 04:35:13PM -0800 References: <Pine.BSF.4.21.0011081625011.1844-100000@yez.hyperreal.org>
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* Brian Behlendorf <brian@collab.net> [001108 16:35] wrote: > > RELENG_4, kernel last updated & built Aug 31st, so apologies if this > touches a problem that was fixed since then. I'd be happy to upgrade > after 4.2-RELEASE goes out if people think there was a fix applied > for this. > > I'm having agonizingly slow disk I/O. Granted, this is a heavily pounded > machine (~2M web hits/day with ~50K being CGI or java, 500K mail > deliveries using qmail, lots of CVS accesses) yet I get spikes in the load > going up to 200 at times, during which the machine's largely frozen to > shell access & other services are much slower. It always comes back (go > freebsd!) but it still feels like I/O is the culprit. The CPU almost > always has idle time available, yet during the day even doing an "ls" in a > moderately sized dir is slow. Here's iostat 5: You have an IO problem that leads to a cascade failure, basically everything starts piling up on the disks, because it's a multiuser machine you're most likley having a lot of sparse access to the drives so unlike your home machine you're probably doing a lot more seeking which is killing performance. I'd get a hardware raid system, they're a lifesaver for IO and reliability. best of luck, -Alfred To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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