[Linux-cluster] Linux-cluster Digest, Vol 70, Issue 9

Bob Peterson rpeterso at redhat.com
Tue Feb 9 14:27:29 UTC 2010

----- "Muhammad Ammad Shah" <mammadshah at hotmail.com> wrote:
| Hi Bob,
| if we are running Database (oracle) on GFS on two node cluster, and if
| node(x) fenced, so this mean that there will be two problems.
|     1. The node(x) File system (ext3) /, /var/, /usr,.... can be
| crashed
|     2. if the insertion was being running, then its lost.
| if i am right on this then its big problem to setup power fencing in
| critical environments. i think it should be some thing different like
| SAN data path fencing.
| one more thing i want to know, if (oracle)node was running it was
| accessing the trace logs, control logs and ..... of oracle, then
| node(x) fenced and node(y) starts will it read from the old
| transaction point or it will be something else (i am not expert of
| oracle) .
| Thanks,
| Muhammad Ammad Shah

Hi Muhammad,

Regarding #1: Each node should have its own root file system separate
from the other node.  Since ext3 has journals too, it should recover
no problem from crashes and being fenced.  Rest assured that I have
fenced systems hundreds, maybe thousands of times with no file system
corruption or data loss for their root ext3 file system.

Regarding #2: I personally don't know oracle or how it manages its data.
I only know that it uses direct io, so takes on the responsibility for
maintaining data integrity.

Regarding #3: I'm not sure what you're asking and I'm not an oracle
expert.  The journal replay feature of GFS should maintain integrity
of the file system.  But oracle's software has to take care of its
own logs and journals within that file system.


Bob Peterson
Red Hat File Systems

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