SAMBA eats up all memory...

William Jojo jojowil at hvcc.edu
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:

  perfagent.tools          2.2.33.13  COMMITTED  Local Performance Analysis &
                                                 Control Commands               

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

[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
need.

> 
> 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
programs.

http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/aixbman/prftungd/memoryuse.htm

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

Check out the online docs here:

http://www.rs6000.ibm.com/doc_link/en_US/a_doc_lib/aixgen/


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)


Bill


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