samba - Feb 1998 - Samba Server Memory Requirements

Hi,

Does anyone know what the server memory requirements are for a Samba
process?
Is it determined by the size of a share or some other factors?

The reason I am asking is because I need to determine if an Ultra Sparc 1
has enough memory to serve 200+ clients.  Currently we have 128Mb of
memory.

Any comments would be appreciated.

Regards

Andy

andy.barsby@tectonic.co.uk

> Does anyone know what the server memory requirements are for a Samba
> process?  Is it determined by the size of a share or some other 
> factors?
> 
> The reason I am asking is because I need to determine if an Ultra Sparc
> 1 has enough memory to serve 200+ clients.  Currently we have 128Mb of
> memory.
> 
> Any comments would be appreciated.
> 
There is one smbd process per user connected ( not per share ).  Total
size is ~2Mb total including swap ( ~1Mb working set ).

I am running about 100 client ( ~one-half connected simultaneously ) on
a Sparc Ultra Enterprise 1 w/6Mb RAM with no problems.  Also running ~50
simultaneous connections on a dual 50MHz Sparc 10 with 128 Mb RAM with
no problems.

Are all 200 connecting concurrently?  Experience has shown here that one
faculty desktops, only about one-half on the client are currently
connected at a time.  You may want to look at the 'dead time' parameter
in smb.conf if there will be a lot of idle time on the client side.




j-
________________________________________________________________________
                            Gerald ( Jerry ) Carter	
Engineering Network Services                           Auburn University 
jerry@eng.auburn.edu             http://www.eng.auburn.edu/users/cartegw

       "...a hundred billion castaways looking for a home."
                                  - Sting "Message in a Bottle" ( 1979
)

on Tue, 24 Feb 1998 08:05:05 -0600  Gerald W. Carter wrote:
> There is one smbd process per user connected ( not per share ).  Total
> size is ~2Mb total including swap ( ~1Mb working set ).
That much?

I use samba on a Linux box (486-100, 20MB RAM, serving up to 20 
DOS/Win311/Win95 boxes). I've measured the memory consumption of 
Samba running 'netstat | grep -c netbios-ssn' and 'free' once
per
minute as a cron job.

On my box, Samba only needs 350..400K per smbd.

There are tree explanations for the difference:
 1. Linux makes smaller programs than Sparc stations.
    (I don't belive it, not 1:4).
 2. The new Samba needs much more memory than my 1.9.16.
    (This would stop my plans to upgrade!).
 3. Jerry is very conservative in estimating

I hope it's number three...

Ludolf

on Tue, 24 Feb 1998 08:05:05 -0600  Gerald W. Carter wrote:
[speaking about Solaris]
> There is one smbd process per user connected ( not per share ).  Total
> size is ~2Mb total including swap ( ~1Mb working set ).
You replied:
| That much?
| I use samba on a Linux box (486-100, 20MB RAM, serving up to 20 
| DOS/Win311/Win95 boxes). I've measured the memory consumption of 
| Samba running 'netstat | grep -c netbios-ssn' and 'free' once
per
| minute as a cron job.
| On my box, Samba only needs 350..400K per smbd.
|
| There are tree explanations for the difference:
| 1. Linux makes smaller programs than Sparc stations.
|   (I don't believe it, not 1:4).
[snip]

	You're seeing a semi-famous change in the way Solaris
	reports memory usage.  There is an article about it at
	http://www.sun.com/sunworldonline/swol-10-1995/swol-10-perf.html
	entitled ``Help! I've lost my memory!''...

	In short, Solaris measures memory use very differently
	than you would expect from BSD-based OSs.  I'll steal
	a quote from Adrian's FAQ:	

A: Look at my SunWorld column entitled "Help! I've lost my
memory!" Then
it may become clear why your calculation does not work. The VM system is
far
more complex than your simple equation presumes. I don't think the
available
data is sufficient to model memory use. In particular,the only data
available on a per-process basis is the size of the address space for
the
process, and the amount that has valid memory mappings. These values can
be
seen (measured in kilobytes) via the old-style ps command, in the SZ
(process size) and RSS (process resident set size) fields: 

% /usr/ucb/ps uax
USER       PID %CPU %MEM   SZ  RSS TT       S    START  TIME COMMAND
root      2026  3.0  2.1 1424 1284 pts/6    O 23:14:29  0:01 /usr/ucb/ps
uax
adrianc   2021  0.7  4.1 3444 2500 ??       S 23:14:26  0:00
/usr/openwin/bin/c
adrianc   1785  0.6 11.110048 6840 console  S 20:50:55  1:12
/usr/openwin/bin/X
adrianc   2024  0.3  1.4  980  856 pts/6    S 23:14:27  0:00 /bin/csh
...

Unfortunately for your calculation, the RSS excludes pages that are in
memory but do not have valid mappings, and it includes pages that are
shared
by other processes. Your calculation also doesn't consider the memory
used
by files that are cached. To obtain this data, kernel code would have to
be
written that traverses many data structures and tallies the pages. This
is
not available in the base release, or in any commercial performance
tools
that I am aware of. 

I think it would be useful to have more information about memory usage,
and
it is on my list of things I'd like to see added to Solaris. 

	I haven't heard anything else since... 
	

--dave
--
David Collier-Brown,  | Always do right. This will gratify some people
185 Ellerslie Ave.,   | and astonish the rest.        -- Mark Twain
Willowdale, Ontario   | davecb@hobbes.ss.org, canada.sun.com
M2N 1Y3. 416-223-8968 | http://java.science.yorku.ca/~davecb