Any foreseenable issue to present a LUN to 2 Windows Hosts.

[MitVongNam]

If both Windows Hosts are configured to perform Read/Write on the same LUN/Volume/Drive? Then am I heading toward diaster or there are tools to arbitrate access between them? Must 2 hosts be clustered? or they can be configured independently to access the same LUN? I am seeking for helps and trying to have a better understandings, not trying to confuse anyone. Thanks in advance.

[Uwe Zessin]

With plain Windows, you will experience file system corruption. That is, because each Windows instance beleives it has exclusive access to the file system and does not even know how to communicate changes to the other server.

Microsoft Cluster Server (MSCS) will not help, because it works on the 'shared nothing' idea: one server as exclusive access to a disk and even locks out the other by use of a low-level SCSI "RESERVE UNIT".

What you need is add-on software like Veritas Cluster (or whatever it is called today) or PolyServe.

[Ivan Ferreira]

To allow access to the same LUN from two windows hosts, you must use a cluster file system like veritas. The Microsoft Cluster does not allow the simultaneous access to the same lun from two hosts, this will cause data corruption. The microsoft cluster allows the access from one host, and if this host fails, the lun is "failed over" to the other host. But never have simultaneous access.

[SAKET_5]

Mitvongnam,

Can I ask what exactly you are trying to setup? I am sure the above two fine responses should have provided you an insight into the issue here.

Are you just looking at building a redundant Windows system that have access to the same "disk devices", so in the case of one server failing - your services failover to the other automatically? Well, if this is what you are trying to do then yes MSCS will do that - cluster members will never do simultaneous read/writes to the disk as the concurrent access lock mechanism will prevent it for a good cause and you should not care - it will provide the fault tolerant solution though! Polyserver as the guys said is another good product.

I will be curious to find out in case your intention is not to build a solution as I describe above then what is it exactly that you are trying to setup?

[MitVongNam]

THANKS. First, I was led to believe that a con-current access design was needed to plan for 2/4 hosts. But the customer clarified and stated that no longer the case. I think The basic MPIO will take care the fail-over issue.

Note: Yes, each host will be installed and configured with dual HBA connections to 2 fabrics.

Again, THANKS.

[MitVongNam]

THANKS. I need to be more pro-active in this MS-Windows business.