Date: Fri, 16 Feb 2001 16:34:52 -0800 (PST) From: Dan Phoenix <dphoenix@bravenet.com> To: Matt Dillon <dillon@earth.backplane.com> Cc: Alfred Perlstein <bright@wintelcom.net>, Jos Backus <josb@cncdsl.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: qmail IO problems Message-ID: <Pine.BSO.4.21.0102161632360.13783-100000@gandalf.bravenet.com> In-Reply-To: <200102060101.f1611Zu55025@earth.backplane.com>
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Ok to finish this off. ....dmesg da0 at sym0 bus 0 target 1 lun 0 da0: <IBM DDRS-39130D DC1B> Fixed Direct Access SCSI-2 device da0: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged Queueing Enabled da0: 8715MB (17850000 512 byte sectors: 255H 63S/T 1111C) da1 at sym0 bus 0 target 2 lun 0 da1: <IBM DDRS-39130D DC1B> Fixed Direct Access SCSI-2 device da1: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged Queueing Enabled da1: 8715MB (17850000 512 byte sectors: 255H 63S/T 1111C) da2 at sym0 bus 0 target 4 lun 0 da2: <IBM DDRS-39130D DC1B> Fixed Direct Access SCSI-2 device da2: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged Queueing Enabled da2: 8715MB (17850000 512 byte sectors: 255H 63S/T 1111C) 3 drives in there as of 3 min ago. just want to take these 3 and raid0 then together as /var. what was recommendation ccd or venim? and has anyone done this before...could walk me through setting these up quickly maybe? Regards, Dan On Mon, 5 Feb 2001, Matt Dillon wrote: > Date: Mon, 5 Feb 2001 17:01:35 -0800 (PST) > From: Matt Dillon <dillon@earth.backplane.com> > To: Alfred Perlstein <bright@wintelcom.net> > Cc: Jos Backus <josb@cncdsl.com>, Dan Phoenix <dphoenix@bravenet.com>, > freebsd-hackers@FreeBSD.ORG > Subject: Re: qmail IO problems > > I think before you guys go off wandering you need some definitive > information on the rate of incomming and outgoing mail, number of > simultanious connections being handled, and so forth. > > On the face of it, high disk transaction rates, low transfer rates, > and idle cpu implies either lots of paging I/O or softupdates isn't > actually turned on. > > Lots of paging I/O implies, potentially, lots of connections. So you > need a couple of stats in-hand to figure out what is going on: > > * How many mail-related processes are running, and by inference how > many simultanious connections are being handled?. 'ps axlww' while > the heavy I/O is going on would help a lot here. > > * Is the sytem paging? 'systat -vm 1' will give you a good indication. > > * 'vmstat 1' output also helps > > If the system is running too many processes then some messing around > with qmail's configuration options should solve the problem. > > Also, nowhere did I read how much memory this machine had. This will > give us useful information on that front: > > * cat /var/run/dmesg.boot > > (And, for gods sake, DON'T screw around with sysctl vfs.write_behind! I > should probably just rip that sysctl out. The default heuristic handles > all the cases already). > > -Matt > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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