Date: Sun, 16 Oct 2005 13:53:54 -0400 From: "Will Saxon" <WillS@housing.ufl.edu> To: "Ronald Klop" <ronald-freebsd8@klop.yi.org>, <stable@freebsd.org> Subject: RE: Disk 100% busy Message-ID: <0E972CEE334BFE4291CD07E056C76ED807738007@bragi.housing.ufl.edu>
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-----Original Message----- From: Ronald Klop [mailto:ronald-freebsd8@klop.yi.org] Sent: Sun 2005-10-16 12:40 To: Will Saxon; stable@freebsd.org Cc: Subject: Re: Disk 100% busy > On Sun, 16 Oct 2005 15:16:34 +0200, Will Saxon <WillS@housing.ufl.edu> > wrote: > > > I am trying to diagnose a problem whereby a virus scanner (clam > > antivirus) is taking too long to scan attachments on a mail server. We > > have an attachment limitation of 20MB and an attachment of 7-20MB can > > take over 3 minutes to scan. This often causes the sending mail server > > to timeout and resend the mail. > > > > In this case, my mail gateway is is a dual 3.06GHz Xeon with 1GB of ram > > and 2 36GB 15krpm drives in a raid-1 on a smart array 6i (cciss) > > controller. I am running FreeBSD 5.4-RELEASE-p1. > > > > Systat -vmstat reports the disk mirror is 100% busy at all times on this > > machine, with an average of around 300 tps at 15KB/t. This seems wrong > > to me, as these numbers are maintained even when the system doesn't > > otherwise appear busy. We don't seem to be swamped by log writes. How > > can I tell what's generating these disk writes? At the moment the 100% > > disk utilization is the only thing I can see that would cause the > > scanning delay. The machine overall is sluggish with file operations. > How many e-mails do you process every second/minute? > Do you use softupdates are is the filesystem mounted 'sync'. > Change the mailserver to first accept the message, then scan it, then > deliver it. In that case you have much more control over how many messages > are scanned at the same time, etc.. I completely forgot that I had the partition mounted 'sync'. That might explain things a bit, huh. I am using qmail - the author indicates that softupdates is not recommended. However, I am going to give it a shot and see if I start losing mail as he suggests may happen. Thanks for answering! -Will
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