Accessing SAN data over smb share?

you can't present that lun to multiple windows server simultaneously ...i mean you can ..but you will cause data corruption as each windows host will try to write its own disk signature to the disk. What's wrong with mapping lun to one server and then sharing it out ?

unless you are running some kind of clustering software then you should not connect a lun to more then one windows host. Even with clustering software ..lun can only be written to by one server, which ever is the owner of that lun at that moment. On the unix side there are file systems that allow parallel access to the file system from multiple unix hosts (http://www-03.ibm.com/systems/clusters/software/gpfs/index.html) ..as far as i know ..no such thing on the windows side. So your only option is to use windows sharing that way you described.

Dunno, that is why I asked

I am new to this so I am trying to understand what the best option is.
The way I understand it, is that you are saying I should never connect more than one server
to a LUN.

I was told I should never connect two hosts to the same storage group but instead connect each host to its own storage group and share the LUN (told by EMC and in training manual)

So is what you are saying not contradicting that? just somewhat confused.
I have no problem sharing it out if it is the right thing to do.

are you doing ESX ? ..or did you mean NTFS

Thanks. I will do that for now and investigate clustering as I don't want one point of failure.
Also, since the windows server will host this, what is the maximum recommended LUN size for this.? I know it is 2TB for VMFS

Oops..sorry, take a look at this link

http://forums.emc.com/forums/thread.jspa?tstart=0&threadID=51742

The first point is - it depends on the application and the intended usage of this storage. If you are setting-up a simple file-sharing application then this strategy is reasonable. If you intend to use this LUN to host high I/O database volumes then this is not a great strategy.

The downsides to the suggested approach:

1) As you mentioned the biggest issue is single point of failure. If the server with the LUN goes down all then everyone loses access.
2) For high I/O applications the SMB (or CIFS) mounted shares will perform very poorly. Basically you are turning 4 servers into users of NAS storage instead of SAN storage.
3) Depending on the application and server design you are most likely routing both your I/O and user access over the same network link. See item #2 on performance risk

The positive:

1) The SMB/CIFS share will handle concurrency so you do not have the data corruption issue to worry about. Once again the intent is locking around regular file sharing NOT attempting to run databases or email servers over the shares. CIFS is not an extremely efficient bulk transfer protocol as that is not its intent.

If you really want NAS storage EMC (and many other vendors to be PC) offer pre-built appliances which either have their own storage or can front-end a unit like the Clariion to provide NAS services. These appliances have built-in clustering to eliminate the single server point of failure.

Without knowing the usage of the LUNs or the reason for wanting to avoid SAN storage (cost issue for HBAs, comfort level, etc.) it is hard to give a definitive answer on this but hopefully this helps a little bit.