Date: Thu, 23 Mar 2000 13:03:44 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Greg Lehey <grog@lemis.com> Cc: Mathew Kanner <mat@cs.mcgill.ca>, Soren Schmidt <sos@freebsd.dk>, freebsd-current@FreeBSD.ORG Subject: Re: ata + vinum problems Message-ID: <200003232103.NAA04161@apollo.backplane.com> References: <20000314182259.I17156@cs.mcgill.ca> <200003150829.JAA22516@freebsd.dk> <20000315095930.A7309@cs.mcgill.ca> <20000315162903.A10174@cs.mcgill.ca> <20000315165410.A3663@mojave.worldwide.lemis.com>
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Ok, this is NOT a softupdates *or* a vinum problem.
This is a buffer cache problem.
The problem is due to the large block size you are using when newfs'ing
the filesystem coupled with problems in geteblk() which causes severe
buffer cache KVM fragmentation. Softupdates exasperates the geteblk()
problem.
I thought I had fixed this problem but apparently not.
Try applying my buf-cleanup-3.diff patch from:
http://www.backplane.com/FreeBSD4/
Then go back to the configuration that was producing the problem before
and see if it still occurs.
Even with the above patch there is still a significant KVM fragmentation
issue with large-block filesystems. You can guarentee 100% success by
hacking the BKVASIZE define in sys/sys/param.h (AFTER applying the patch)
from 16384 to 32768, but I wouldn't raise it much beyond that. This
patch is only a partial fix to the problem.
-Matt
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