SAMBA eats up all memory...

William Jojo jojowil at
Thu Jul 6 12:37:50 GMT 2000

Sumitro Chowdhury wrote:
> Hi,
> 1. (A) high water mark and low water mark are set to 0
>    (B) maxrandwrit = 0 in vmtune
>     So I would say I/O pacing is off and write behind is off.

Okay...I thought so...

> 2. Since avm in vmstat is not increasing, there does not seem to be
>    any memory leak. but the system is CERTAINLY running out of memory.
>    This is what is frustating that I canNOT "see" how system can run
>    out of memory without a) memory leak b)heavy paging.

Actually, that's not entirely accurate. This is the amount of memory in use by
programs, not AIX proper. IOW, if you have:  COMMITTED  Local Performance Analysis &
                                                 Control Commands               

installed, run the following (if not, I *strongly* suggest you get it from the

[storage:/] # svmon

               size      inuse       free        pin    virtual
memory       784359     742339      29687     784359      63734
pg space     786432      32823

               work       pers       clnt
pin           30423          0          0
in use        64830     677475         34

[storage:/] # vmstat 2
kthr     memory             page              faults        cpu
----- ----------- ------------------------ ------------ -----------
 r  b   avm   fre  re  pi  po  fr   sr  cy  in   sy  cs us sy id wa
 0  0 63479 29957   0   0   0  10   22   0 134  380  66  1  2 93  4
 0  2 63479 29955   0   0   0   0    0   0 435 2412  55  0  1 98  0
 0  2 63479 29955   0   0   0   0    0   0 431  211  49  0  0 99  0
 0  2 63479 29955   0   0   0   0    0   0 444  215  53  0  0 99  0             

As you can see, I have a 3GB system, but only 250+MB is tied to processes
(work), the rest is in file caching (pers) or is free.

> 3. lsps -a:
>     Page Space  Physical Volume   Volume Group    Size   %Used  Active  Auto
>   Type
> paging00    hdisk1            rootvg        1024MB       1     yes   yes
> lv
> hd6         hdisk0            rootvg         512MB       1     yes   yes
> lv
>    Essentialy there is no disk paging.

Which makes sense, since maxperm is 10% - the VMM will leave working pages alone
and aggresively steal file pages to minimize paging. What you did was correct
but overkill. I would leave maxperm at 80%. This would give 6.4GB to files and
1.6 to programs and the kernel. The system should still aggresively steal file
pages and not do swapping since you only require ~1GB at present. If paging does
begin, reduce maxperm by 5% until it stops and levels off but try to stay at 50%
or higher since the VMM is designed to page to disk as well and is pretty smart-
you should always look at avm from vmstat to see exactly what your processes

> 4. vmtune output:

see above ;)

> 5. I would also tend to agree that MACs are screwing things up but they
> require proof. What troubles me is that when MACs and NT stop
> writing to the shared file system, I can't copy , move , rm 50MB
> files from the AIX prompt even. I get system out of memory errors on the
> screen. Nothing on errpt though and as u saw, avm is around 1GB.
> What's happening to the rest 7GB of memory ???

Check out this web page from IBM. It'll help you discover memory leaks in

Use smbstatus to get the pid's of suspicious clients and get the proof you need.

Check out the online docs here:

There is more:

What's the current number of processes running and what's the maxuproc value of
lsattr -El sys0? Are all your smbd's running as root (which they should be)?

I ask because this is an argument I have with IBM right now that maxuproc as of
4.3.3 (but not 4.3.2 or lower) seems to affect root (uid 0) when it should not.

Also what are the ulimit -a values for root and everyone else? these are also
stored in /etc/security/limits. You may simply be hitting a data segment or rss
wall which would look like your system is out of memory or, more to the point,
like you have a memory leaky program (which I really don't think you do...the
Samba Team has worked their asses off to make sure this code is clean and fast)


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