Read-only LUN partition
Hi,
I have an server running Red Hat Enterprise Linux Server release 6.4 which is getting a LUN from IBM DS8700 through multipath and its running fine most of the time. Just randomly the LUN partition gets into read-only mode.
The /var/log/messages does not show up anything.
I am not very clear where to troubleshoot, whether the FC port, Cable or anything else. Kindly advise on how to approach this.
Regards,
Ritesh Vishwakarma
Responses
Pro
484 points
Hi Ritesh,
You did not describe what kind of hardware you are using on the server side. Is it a blade or standalone-server, or a virtual machine? And what brand (IBM, HP, Dell, and so on).
/var/log/messages should show some "read-only" alerts. It is advisable to check how your syslog is set up.
In parallel with it, you should look for FC SAN switch logs, SAN (IBM DS8700) logs too and server hardware logs (FC card problems, cabling, and so on). They should contain some clues. They always do but the question is who has access to them.
Regards,
Dusan Baljevic (amateur radio VK2COT)
Guru
10153 points
Ritesh,
I've had a few RHEL systems that mark an external SAN lun/mounted partition as read only - and after rebooting the system, the read-only goes away. I could not by remounting mount -o remount,rw /path/to/mounted/san make it mount as read-write. I had to reboot the system in the few situations where there was this issue. In our situation, there was an issue on the storage end. It's been so long, I can't exactly remember, but it might have been related to power, or something else perhaps. However, when I faced the read-only issue that would not be cured by the above command, in the cases I faced it, a reboot resolved it. Sad but true.
This does not occur very often, I'd say 3 times in many years.
Regards
RJ
Welcome! Check out the Getting Started with Red Hat page for quick tours and guides for common tasks.