Problem with ufs not releasing vm_pages on busy volume.

Q qdolan at
Wed Aug 2 10:10:14 UTC 2006


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  



                           _____  /  Quinton Dolan - qdolan at
   __  __/  /   /   __/   /      /
      /    __  /   _/    /      /        Gold Coast, QLD, Australia
   __/  __/ __/ ____/   /   -  /            Ph: +61 419 729 806
                     _______  /

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