[Samba] SAMBA Cluster or .......

Marcin Giedz giedz at arise.pl
Fri Mar 9 10:45:50 GMT 2007


My question is quite related to this topic. Currently I work for one of 
brokerages and prepare to set up domain for all employees. However I 
must be sure that if my PDC fails my BDC will provide all connections to 
roaming profiles and extra shares (to be mounted during the log in 
process). But additionally I want to have only ONE storage place for 
placing every shares and profiles. Lucky, I "found" one EMC disk array 
to be used in this solution. My idea is connect 2 server (PDC and BDC) 
over FCs to ONE storage. I don't have any extra software like "cluster 

Now I have almost everything UP and running but found this "thread" 
about "data consistency" where different Samba instances may cause data 

Please NEVER export the same file space via different Samba
nodes, this leads to data corruption because the locks
propagated have the wrong semantics...."

Now I'm wondering if I can really do this? According to what Volker said 
my solution/idea is (in a word) - BROKEN :(
Does this me that I must use some extra software between EMC storage and 
Samba instances to prevent data lost? In my situation there is a  chance 
that PDC and BDC will server THE SAME file for different users.

So looking at this topic I'd come to think that I CAN'T go production 
with such prepared PDC + BDC + EMC storage - am I right? If yes would 
anyone propose any solution for such idea?


Volker Lendecke napisał(a):
> On Fri, Mar 09, 2007 at 09:02:19PM +1300, Jason Haar wrote:
>> ?? doesn't that contradict the smb.conf man page?
>>          "Kernel oplocks support allows Samba oplocks to be broken
>> whenever a
>>           local UNIX process or NFS operation accesses a  file  that 
>> smbd(8)
>>           has   oplocked.  This  allows  complete  data  consistency 
>> between
>>           SMB/CIFS, NFS and local file access (and is  a  very  cool 
>> feature
>>           :-)"
>> I read that as meaning you get complete data consistency between SMB,
>> NFS and local file access :-)
>> Ahh. I just found the posting you refer to. You're saying the above only
>> works if the Samba server is also the NFS server? Not an NFS client?
>> I'm really surprised at that
> This means that yes, we get data consistency when Samba and
> other Unix processes access the same file space.
> In this sense Samba does not count as a normal Unix process
> because it has to fulfil other locking requirements on
> behalf of its clients. It is these locking requirements that
> go beyond what Posix can provide that lead to data
> corruption when multiple Windows clients access the same
> file space via different Samba instances.
> Volker

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