Problem with ufs not releasing vm_pages on busy volume. (soft
qdolan at gmail.com
Tue Aug 8 05:14:19 UTC 2006
On 02/08/2006, at 8:10 PM, Q wrote:
> I have a problem that seems to be related to something ufs related
> not releasing some vm_pages on busy filesystems. I have two servers
> running PostgreSQL, one running 6.0-RELEASE, the other 6.1-RELEASE.
> Both are under the same (fairly heavy) load, performing the same
> operations in bursts every five minutes. The filesystems in
> question are 450-500Gig, each server using a different brand of
> RAID card, they both have soft-updates enabled.
> The problem is that both servers are seeing an accumulation of
> about 100Mb of active pages per day (looking at
> vm.stats.vm.v_active_count) that never get released. The only way
> to release these pages is to unmount the filesystem and remount it.
> Failing to do this results in the server eventually locking up.
> If someone could provide me with some direction on how to go about
> tracking down what might be causing this to happen it would be much
I have narrowed the cause of this issue down further to something to
do with soft updates. If I turn off soft updates for the filesystem
hosting the database the system no longer accumulates active vm_pages
constantly. Instead for accumulating 100Mb a day of active vm pages
until all memory is consumed, it will hover around 50-60Mb with soft
If someone familiar with the softupdates code is willing to help me
pinpoint the cause of this problem it would be much appreciated.
_____ / Quinton Dolan - qdolan at gmail.com
__ __/ / / __/ / /
/ __ / _/ / / Gold Coast, QLD, Australia
__/ __/ __/ ____/ / - / Ph: +61 419 729 806
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