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XP1024 shared disk problems.

XP1024 shared disk problems.

I've allocated 1 14Gb open-E disk to a LINUX cluster with RW access (lets call this cluster 'Server A' and the same disk to a non-clustered LINUX server with Read Only access (lets call this 'Server B'.)

On server A I mounted the disk and created 3 files. I mounted the same disk on server B and can see those files. On server A If I add data to those files or add new files I don't see the changes from server B. I still only see the original 3 files. On server A I can see the changes. What gives?

Server A = Red Hat Enterprise Linux AS release 4 (Nahant Update 1)

Server B = Red Hat Enterprise Linux AS release 3 (Taroon Update 7)

Why isn't the new data from Server A seen on the same shared disk on Server B?
5 REPLIES
Nigel Poulton
Respected Contributor

Re: XP1024 shared disk problems.

Hi Jeff,

Before digging deeper can I just check that its not something like the fact that the data hasnt been flushed to disk (sync'd) and therefore the data still in local cache on your Linux servers?

What about if you unmount the volume on server B and then remount it?

Mackem
Talk about the XP and EVA @ http://blog.nigelpoulton.com

Re: XP1024 shared disk problems.

I tried unmounting and remounting and get the same results. It is beginning to look like a LINUX file system 'feature'. Logically this should be do-able with the XP1024 shouldn't it?
Nigel Poulton
Respected Contributor

Re: XP1024 shared disk problems.

Jeff,

This is absolutely doeable on the XP1024. You can present a single LUN to hundreds of hosts should you ever be crazy enough to want to do that.

It is more than likely going to be a host related problem.

The only thing that springs to mind that might stop access to a LUN would be if the clustering software palced a SCSI reserve on the LUN that prevented other hosts from accessing it. However, you would more than likely get an error when trying to mount or read from the LUN if this were the case. Windows normally gives an error such as "Device not ready" if a host tries to access a LUN with a SCSI-2 reserve on it.

Which filesystem are you using?

mackem
Talk about the XP and EVA @ http://blog.nigelpoulton.com

Re: XP1024 shared disk problems.

The file system is EST3.
Nigel Poulton
Respected Contributor

Re: XP1024 shared disk problems.

OK

Either Ive been away from Linux for longer than I thought, or you actually meant to say EXT3 ;-)

You say that when you unmounted the disk and then remounted it you still got the same problem. Can you just clarify this for me -
When you remounted the disk could you then see the new files that were previously created, but then had the same problem where you could not see any more that were created after it was remounted?

mackem
Talk about the XP and EVA @ http://blog.nigelpoulton.com