Multiple Server access to same disk

[Rob]

Group,

In windows a general no no but can anyone describe
technically how the OS behaves when attempting to access a
disk already in use by another server.

This is a possible scenario in Storage Area Network
configurations.

Thanks In Advance

Rob

 

[NuT CrAcKeR]

VAX VMS is the only platform/OS that can have multiple hosts accessing the
same physical disks, at the same time.

In the MS world, even with SAN, you need a clustered implimentation. And
even then, there can only be one node in the cluster that has access to the
volume on the SAN.

What point is it that you are trying to make??? That is, are you looking to
dispell a myth with co-workers, etc... ?

NuTs

 

[Richard Blincoe]

Very simple - if two servers are acceessing the same disk and are not
clustered to provide a mechanism for locking disks and controlling access -
you will very rapidly have a corrupted disk.

Any decent SAN will have some sort of lun masking software so that when you
have more than one server attyached to a fibre port (via switches or hubs
etc) that you control access to the luns on that port, normally by giving
access permissions on a WWN (World Wide Name - unique id for the fibre port
in the server) basis..

 

[rob]

I have a complex SAN which has hardware replication and
mirrorining in place for backup. Only the copied volumes
are accessed by the backup servers.

I understand multiple access to same disk screws the disk,
I ask the question to understand exactly what happens when
two servers access the same volume, ie will the servers
write new signature to unknown/new disk, does disk become
unreadable to both, will the OS crash, etc etc..... really
it a questiopn for MS developers but I figured some one
here might know!