[Samba] Clearcase, Samba, and mnode values

Volker Lendecke Volker.Lendecke at SerNet.DE
Wed Sep 7 14:19:23 MDT 2011

On Wed, Sep 07, 2011 at 11:48:11AM -0700, Kathy wrote:
> Hi all --
> I recently temporarily deployed an upgraded Clearcase server (
> on 64 bit RHEL 5.6.  With it I was using Redhat's release of Samba for
> that version of the OS -- 3.0.33.    The system has 32 GB of memory
> and within 12 hours, it would be down into swap.  Maximum active
> licenses used is 36 but a more typical load is 18-25 users having a
> Clearcase license at once.  Clearcase clients are on Windows.  This
> server is the whole shebang  -- license server, view and vob server.
> All disks are local, no NAS.  Most of the time our developers are
> using snapshot views but merge into the dynamic views.
> It looks to me like I have a memory leak, and IBM is blaming Samba,

Main question is: Do the smbd processes really consume all
that memory?

> seeing that I was using an unblessed version of the tool.  Apparently
> 3.0.32 is blessed and 3.0.33 is not.  Although I'm skeptical, I'm
> willing to entertain the idea that a 0.01 release change could be the
> problem, so I recently updated to 3.5.8, which apparently is blessed
> to work with  This system is now a test server so we can test
> it without impacting production use.  We still need to do some load
> testing on it.  The original server is on different hardware (still
> Dell, though), running 32 bit RHEL 5.2 and Clearcase, and
> Samba 3.0.28 (which also apparently isn't blessed by IBM but has never
> had any problems).  I am using the samba smb.conf file for both
> releases/servers.
> For those of you who are familiar with how Clearcase and Samba work
> together, my questions are the following:
> 1.  What is typical memory usage with Clearcase and Samba?  Is it
> typical for it to cache all memory, eat into a little bit of swap (say
> 312k) and then sit there like that and work just fine?  Or should I
> expect it to eat up initially a few gigs of memory and then stay
> relatively stable, recognizing that over time the running system will
> slowly eat up memory (but not all in 12 hours).
> 2.  IBM has suggested making sure these conditions are met for mnode
> values on Windows clients and the MAX_OPEN_FILES is big enough on the
> Samba side:   https://www-304.ibm.com/support/docview.wss?uid=swg21169548
> Basically saying that for a 64 bit Clearcase/Samba server, the max
> mnode values should be set to 800 and not the default 1800.
> Anyone with experience with this?  We have not seen the particular
> errors mentioned in this article, but IBM support is telling me about
> it as a guideline.  Also mentioned in the article is MAX_OPEN_FILES.
> My current value for that is 16,384.   How do you know what is an
> optimal value for that for your system?
> Thanks for any input.  I have asked IBM to describe typical memory
> usage but so far I'm not getting any solid answers.
> Kathy
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