MSA issue on linux

[Sherif A. Louis]

I installed linux Redhat ES4U2 on 2 proliant servers DL580 and i had an MSA disk array containing 4 LUNs. The client requested that the MSA LUNs be visible by both servers at the same time and mountable. So i changed the presentation of the LUNs from the ACU to all smart arrays. so both servers can now see all the LUNs. Then we partitioned them as the client requested using ext3 file system.

The problem is i mounted a partition on node 1 then went to node 2 and mounted the same partition. Now how is this possible? and what can i do to prevent this from happening again? knowing that when i created a file on node 1, node 2 was updated by the new file! Thank you.

[Uwe Zessin]

> The client requested that the MSA LUNs be visible by both servers at the same time and mountable.
> Now how is this possible?

It is possible because the storage array just presents data blocks. The ext2/ext3 file system assumes exclusive access to a disk, so it does not even attempt to lock-out other servers, e.g. by using a SCSI reservation.

Unfortunately it is missing the ability to work together with another server accessing the same disk. By mounting the file system on the second server you have started corrupting it.

You do need a shared file system if your customer wants proper shared access from both servers.

[Sherif A. Louis]

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