john@accord.cc.iastate.edu (Hascall John Paul) (01/11/91)
We have a machine which frequently hangs with "cant get mbufs"
splattered all over the console. I am way out of my league
here, any clues or pointers will be much appreciated. The machine
is a DECstation 5000/200CX with 24 MB memory, 8 RZ57s and a TLZ08.
Here is a vmstat, for what it's worth (I note that the Total
Allocated number just keeps growing, it was ~ 800 KB right
after booting, is there some upper limit?)
Many thanks,
John Hascall john@iastate.edu
---------------------------------------------------------------------
john@fs-1> vmstat -K
:
:
Total Allocated = 2000 KB; Total Free = 617 KB
Memory Usage: Type and Number
MBUF 477 DEVBUF 1 PCB 88 ZOMBIE 1
TEMP 10 MOUNT 10 NFS 358 CRED 5
RPC 2124 RMAP 1 SOCKET 59 RTABLE 4
IFADDR 2 SONAME 1 CLUSTER 173 X_DADDR 25
--
John Hascall An ill-chosen word is the fool's messenger.
Project Vincent
Iowa State University Computation Center john@iastate.edu
Ames, IA 50010 (515) 294-9551rcmart@rwb.urc.tue.nl (Mart Mennen) (06/03/91)
Since a few days we have a very nasty problem on our DECsystem 5400, which runs under Ultrix 4.0. After a timeperiod of about 7 hours the system reports "cant get mbufs" on the console and then the system hangs! Nothing interesting is found in errorlogs and syslogs. We also checked for ethernetproblems as this system has a lot of NFS-clients, but untill now we have not encountered strange things in that area. Is there anyone who has suffered from this same problem or has any suggestions for solving the problem? Thanks for your time. -- Mart Mennen, Eindhoven University of Technology Computing Centre 1.99, +31 40 472164 P.O.Box 513, 5600 MB Eindhoven, The Netherlands E-Mail: rcmart@urc.tue.nl
farrell@pangea.Stanford.EDU (Phil Farrell) (06/04/91)
In article <rcmart.675956786@rwb.urc.tue.nl> rcmart@urc.tue.nl writes: > >Since a few days we have a very nasty problem on our DECsystem 5400, >which runs under Ultrix 4.0. >After a timeperiod of about 7 hours the system reports "cant get mbufs" >on the console and then the system hangs! "mbufs" are the memory areas used to queue incoming and outgoing ethernet packets. You can see how many are in use with "vmstat -K". The number allocated by the system is a function of the "physmem" and "maxusers" kernel configuration parameters. Perhaps your network load is simply too great for the values you have configured into your kernel. You could try increasing either or both of these parameters and building a new kernel. By the way, DEC lore (that is, what the support engineers tell you, not what the documentation says) is that the "physmem" parameter on RISC systems should not be set equal to the actual amount of physical memory, but rather to at least 125% of actual memory in order to properly size system tables, particularly the PTEs that map between physical and virtual memory. On the other hand, you may be seeing a pathological condition where mbufs are not being properly freed. I can't help you with that possibility and have my doubts that DEC can either. -Phil Farrell, Computer Systems Manager Stanford University School of Earth Sciences farrell@pangea.stanford.edu