[Samba] File locking problem involving Samba, Clearcase, and Cygwin

Brian Cowan brcowan at gmail.com
Sat Feb 7 05:00:26 GMT 2009

Kathy wrote:
>> [views]
>>        comment = Flint views
>>        path = /view
>>        read list = @cozcmusr, aramac
>>        write list = @cozcmusr
>>        read only = No
Kathy, I work in ClearCase support, and this construct is not supported 
by IBM. It's not a tested configuration. There is a mechanism -- 
export_mvfs -- that allows hosts that do not have ClearCase installed to 
access files in dynamic views via NFS. You are trying to accomplish the 
same thing by sharing the MVFS root (/view -- translation for non-CC 
people: Think "path=/net"). Is there a pressing reason for doing this? 
Wouldn't it be simpler to install ClearCase on the PC's and access the 
files through the Windows-Native MVFS (which in turn would access the 
VOBs on your VOB server)?

That being said, I doubt that it's the MVFS confusing Samba, but it is 
possible. If this turns out to be a load-related issue, the MVFS may 
show this issue more often because it does a lot more under the hood 
than most filesystems (version selection, getting cleartext constructed, 
etc). I would recommend testing to see if you can make the same thing 
happen with files in:
1) A local filesystem
2) a remote NFS-mounted filesystem.

You may need to increase the load on the Samba server 2-fold or more to 
get it to "fall over" in the same way, but definitely try. If so, then 
ClearCase has been eliminated from the picture and you can start trying 
various debugging tricks to see why Samba thinks some users have oplocks 
when they shouldn't.

By the way, I suspect that you have a case open with us about this 
issue, if so, can you send me the PMR number?

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