I am using similar design for our disaster site, but not on DataDomain.
Exactly the same procedure is used during each disaster site testing.
Some important comments:
1) NFS file systems have to be mounted as "soft" (not default "hard") to
prevent any hanging operations. AIX gives error for soft mounted NFS file
system. For hard mounted NFS file system I/O operation is hanging with very bad
consequences for TSM Server;
2) setting status "unavailable" for remote copy pool stops all operations, but
does not prevent read or right errors for volumes in unavailable FILE pool in
case of scheduled copy or space reclamation;
3) involved volumes can be marked as "readonly" with following manual
correction after completion testing or maintenance.
4) TSM Server is able to use NFS file systems mounted back after exercise
without any problems, but see points 1-3.
Grigori G. Solonovitch
Senior Technical Architect Ahli United Bank Kuwait www.ahliunited.com.kw
Please consider the environment before printing this E-mail
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Richard Rhodes
Sent: 06 07 2012 8:07 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] changing stgpool to access=unavailable
On Monday evening I have the first occasion to perform some maintenance on one
of our DataDomain systems. Our DD's are all setup for NFS access, so they are
using FILE device type pools.
The plan is to:
- stop all processes/sessions writing to the DD based FILE stgpools
- mark the stgpool access=unavailable
- umount the NFS filesystem
- perform the DD work
- mount the NFS filesystem
- mark stgpool access=readwrite
Question: What happens when a pool is changed to "access=unavailable"?
With tape, I can mark drive offline and the current process will keep writing
to it until it finishes.
Is the same true with access=unavailable for a FILE dev pool?
In other words, can I mark it unavailable FIRST, and then cancel any
processes/sessions using it. This would prevent the wack-a-mole of
sessions/processes starting as I cancel others.
(note: disk pool will still be available during this work. The disk pool has a
max size threshold set to force big files directly onto the DD. )
Rick
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