Date: Fri, 2 Oct 2009 10:23:35 -0400 From: "Grant Peel" <gpeel@thenetnow.com> To: <freebsd-questions@freebsd.org> Subject: "Out of mbuf address space!" Message-ID: <88CD8D18ADF4405DAA81B43F941698A5@GRANT>
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Hi all,
I have an older RAID 5 machine running FreeBSD 5.2.1 and am using it as =
a backup storage unit.
Yesterday morning, we noticed the the NFS mounts on the clients to this =
machine we not available, which sent a bunch of cronjobs spinning out of =
control etc. We also became unable to connect via ssh.
Once at the console we noted sevral dozen entries in the messages.log:
Oct 1 08:32:13 enterprise kernel: Out of mbuf address space!
Oct 1 08:32:13 enterprise kernel: Consider increasing NMBCLUSTERS
Oct 1 08:32:13 enterprise kernel: All mbufs or mbuf clusters exhausted, =
please see tuning(7).
After rebooting the machine, and getting the clients under control I =
started investigating tunning(7) in the man pages.
I am confused however.
I have increased the kern.ipc.nmbclusters to 2048 in the =
/boot/loader.conf, but when I checked netstat -m, it appears that there =
are less buffers available then there were when the problem happened.
netstat -m
enterprise# netstat -m
mbuf usage:
GEN cache: 0/64 (in use/in pool)
CPU #0 cache: 145/640 (in use/in pool)
Total: 145/704 (in use/in pool)
Mbuf cache high watermark: 512
Maximum possible: 4096
Allocated mbuf types:
144 mbufs allocated to data
1 mbufs allocated to packet headers
17% of mbuf map consumed
mbuf cluster usage:
GEN cache: 0/232 (in use/in pool)
CPU #0 cache: 135/232 (in use/in pool)
Total: 135/464 (in use/in pool)
Cluster cache high watermark: 128
Maximum possible: 2048 =
<-- this number was much higher
22% of cluster map consumed =
<- this number was much lower.
1104 KBytes of wired memory reserved (27% in use)
0 requests for memory denied
0 requests for memory delayed
0 calls to protocol drain routines
This particular machine has 512 MB of ram.
Any suggestions what an NFS intensive machine with 512 meg ram should =
have kern.ipc.nmbclusters set to?
Are there any otyher tunables I should be looking at.
-Grant
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