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eva5000 OS Unit ID and LUN for and Open Vms cluster system

 
salomon_4
Occasional Visitor

Re: eva5000 OS Unit ID and LUN for and Open Vms cluster system

I want to jump in with another topic.
We have HP SAN and Windows 2000 servers
What is your experience with presenting a vdisk to more than one server (lets say 2). Can the vdisk be accessed from the 2 servers at the same time? Is there any disadvantage?

Thanks in advance, salo
Jan van den Ende
Honored Contributor

Re: eva5000 OS Unit ID and LUN for and Open Vms cluster system

Salomon,

Welkom in het VMS forum!, maar...


Of course it is very common to access a SAN disk (or ANY disk at that, only since 1984) directly from multiple systems, but... I am stricktly talking VMS here!
Since you mention W2K, it looks much like you are referring to Micro$oft kind of stuff, and THEN I guess that trick is still way far ahead in the not-yet-foreseeable future.

Nou effe serieus:

I guess you landed in the wrong forum for your question.
You stand far better chances of an educated answer in the Storage and/or the Mickey forums.

Good luck there!
and don't hesitate to come back here if you have any VMS questions, or just want to find out about it :-)

Jan
Don't rust yours pelled jacker to fine doll missed aches.
Willem Grooters
Honored Contributor

Re: eva5000 OS Unit ID and LUN for and Open Vms cluster system

Salomon,

The answer to your question has been answered already: YES, you could have 2 servers accessing the disk, and YES your data WILL be corrupted.
That's because you're using Windows "Clustering" (Mind the quotes).
Bare in mind that if Windows has trouble with 2 servers (their max?) what it would be if you had 96 (the official max for VMS).
The reason:
Windows, nor any Unix (or likewise) is 'cluster-aware' so you have to be VERY cautious on what you want to achive.
The _only_ environment where you can present a single disk (virtual or not) to multiple servers, and access it _simultaniously_ from ANY system in the cluster, without having to worry a bit about corruption, is VMS.

Your problem is your OS. Not your disks.

Willem
Willem Grooters
OpenVMS Developer & System Manager
Christopher Nichols
Occasional Visitor

Re: eva5000 OS Unit ID and LUN for and Open Vms cluster system

Back to the original question for a moment.

Is the OS Unit Id for the VD used after the LUN is presented? If it is, what impact would it have if the OS Unit Id changed while the LUN is presented? In other words, can the OS Unit ID change while the LUN is presented, or does the LUN need to be unpresented, then change the ID, then present again?

Sorry if this seems like a simple question, but I don't know anything open openVMS.