RE: storage and filesystems on linux (ocfs2, ASM...)

  • From: D'Hooge Freek <Freek.DHooge@xxxxxxxxx>
  • To: Jonathan Smith <smithj@xxxxxxxxxx>
  • Date: Tue, 14 Jun 2011 01:05:16 +0200

Oracle is doing syncing for you.
When you use local homes, the installer will clone the software to the other 
nodes at the end of the installation.

When using linux multipathing you can specify what has to happen when all paths 
to a lun are unavailable. One option (don't know if this is the default) is 
"queue if no path", which let the io's just wait when no path is available 
(yes, sometimes the options are pretty descriptive  ;-)  )
At that moment it is the css timeout (heartbeat to the voting disks) which will 
kick in and reboot the node.

I'm not familiar enough with ocfs2 to know if there are some timeouts on that 
level.

In Redhat / OL 5 it is possible to add / remove luns (or paths to luns) without 
forcing the HBA to rescan the fabric (I have done so last week).
In RH / OL 4 it should also be possible, but I never succeeded.
See the redhat online storage reconfiguration guide: 
http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Online_Storage_Reconfiguration_Guide/index.html

In your orginal post you said that your system crashed on average once a week 
because of this rescanning. Is so often that something changes to the paths 
between your rac nodes and the storage?


Regards,
 
Freek D'Hooge
Uptime
Oracle Database Administrator
email: freek.dhooge@xxxxxxxxx
tel +32(0)3 451 23 82
http://www.uptime.be
disclaimer: www.uptime.be/disclaimer

-----Original Message-----
From: Jonathan Smith [mailto:smithj@xxxxxxxxxx] 
Sent: dinsdag 14 juni 2011 0:40
To: D'Hooge Freek
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: storage and filesystems on linux (ocfs2, ASM...)

Thanks for the reply.

We have Oracle, HP (hardware, SAN switches, HP EVA), and Red Hat (OS) tickets 
open. So far all are pointing fingers at each other.

Our other systems also use qlogic, but ocfs2 is the only one which panics due 
to a rescan. Other filesystems notice the event, write out a warning in the 
log, and continue to function. The rescans are happening because of a routine 
fabric event: adding a path, losing a path, new device zoned in, etc.

When doing the individual node-local installs, how do you make sure everything 
is in-sync?

        Jonathan Smith

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