2.3 and FreeBSD

[The Hermit Hacker]

On Sun, 1 Aug 1999, N wrote:

> # ps -axflc -Unews
>   UID   PID  PPID CPU PRI NI   VSZ  RSS WCHAN  STAT  TT       TIME COMMAND
>     8 13246 20628   4   2  4  6756 5856 sbwait IN    ??    0:03.48 perl
>     8 13247 20628   4   2  4 43488 4524 select IN    ??    0:00.79 innfeed
>     8 18676  8530   0  10  0   176   40 nanslp I     ??    0:00.00 sleep
>     8 20628     1   9 -22  0 83148 27652 vmpfw  Ds    ??  755:29.10 innd
>     8  8528     1   0  10  0   540  136 wait   I     p0-   0:00.00 sh
>     8  8530  8528   0  10  0   560  200 wait   I     p0-   2:07.74 sh
> # 
> 
> Not doing anything anymore... 3.2-STABLE from just over a month ago.
> Marc, did you ever find a solution to the problem?  IIRC you saw exactly
> the same symptoms. (This time it's a dual PII-400 with 768 MB.)

After extensive debugging with Matt Dillon, it turns out that pre-4.0
kernels have a VM fragmentation bug that appears to be the major cause of
my problem, and which is something that is going to seriously impact
*anyone* running FreeBSD pre-4.0 kernels...

IN my case, the fix: doubled the RAM so that swap is used alot less.

A good way of checking to see if this is affecting you is to check the "VM
pgdata" values in vmstat -m:

    VM pgdata  1586   352K   9398K128695K    13805    0     0  

When the 3rd value (9398K) approaches or exceeds the 4th (128695K), expect your system to lock up shortly afterwards...


Marc G. Fournier                   ICQ#7615664               IRC Nick: Scrappy
Systems Administrator @ hub.org 
primary: scrappy at hub.org           secondary: scrappy@{freebsd|postgresql}.org