John,
We make use of both the backup and HSM clients and in the event that a HSM
disk/filesystem is lost you need to recover using the backup copies of files
(regardless of whether you choose to restore just the stubs - which would be
a sensible thing to do). Should you lose an individual file, you would
again use the backup copy of the file. The migration storage hierarchy is
used only to migrate and recall files as necessary.
Each of the two storage hierarchies really needs BACKUP STG to protect the
data in the respective hierarchies - so you pay quite a price for optimal
protection. Files that have already been migrated before the client
requests a backup can be backed up without having to be recalled to the
client first; this is called cloning and adsm will copy a file from the
migration stg hierarchy into the backup stg hierarchy on the server.
You should be aware that the linkage or knowledge of a file is primarily on
the client : it knows that a file is migrated and that it is backed up;
adsm server knows about the "two files" as essentially separate entities.
Hope this helps, regards, Sheelagh
------------------------------------------------------------------------------
Sheelagh Treweek Email: sheelagh.treweek AT oucs.ox.ac
DOT uk
Sheelagh Treweek Email: sheelagh.treweek AT oucs.ox.ac
DOT uk
Oxford University Computing Services Tel: +44 (0)1865 273205
13 Banbury Road, Oxford, OX2 6NN, UK Fax: +44 (0)1865 273275
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> From owner-adsm-l AT VM.MARIST DOT EDU Thu May 21 23:00:18 1998
> From owner-adsm-l AT VM.MARIST DOT EDU Thu May 21 23:00:18 1998
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
> Date: Thu, 21 May 1998 16:32:55 -0500
> From: John Valdes <j-valdes AT UCHICAGO DOT EDU>
> Subject: HSM, Backup & Copy Storage pools
> To: ADSM-L AT VM.MARIST DOT EDU
>
> Hello all,
>
> We have a fairly new ADSM installation, and are primarily making use
> of ADSM's HSM capabilities. In a typical configuration, a local
> filesystem on the HSM client (Unix) migrates data to a primary disk
> storage pool on the (AIX) ADSM server, which in turn migrates to a
> primary tape (3590) storage pool. I want to ensure that all the data
> under HSM control is backed up to protect against media (disk or tape)
> failure. However, I'm unsure as to the best way to do this ("best"
> being a method that combines complete backup with easy (preferably
> automatic) recovery of data). Given the above configuration, complete
> backup means that the local disk on the HSM client (containing stub
> files and unmigrated data), the disks in the primary disk storage
> pool, and the tapes in the tape storage pool are all backed up.
>
> >From what I've read in the manuals, the normal way to backup the HSM
> filesystem (local disk plus data migrated to storage pools) is to
> simply use the ADSM backup client. This sound fine, except how is
> file recovery handled? If a file somewhere in the HSM system (local
> disk, disk pool or tape pool) is damaged, does ADSM automatically
> recover the file from the backup storage pool used by the backup
> client, or must one restore the file manually?
>
> In the ADSM Admin Guide, it describes how to use copy storage pools to
> back up primary storage pools. Using a copy storage pool has the nice
> feature that if a file in a primary storage pool is damaged, ADSM will
> automatically retrieve the file from the backup in the copy storage
> pool, without requiring operator intervention. However, the copy
> storage pool only backs up primary storage pools; it doesn't backup
> the local filesystem residing on the HSM client, so there is the
> potential of losing unmigrated data (and stub files, although it
> sounds like these can be restored using dsmmigundelete).
>
> Is there any way to combine the comprehensive backup of the
> backup/archive client with the automatic restoration of copy storage
> pools? If so, how?
>
> John
>
> -------------------------------------------------------------------------
> John Valdes Department of Astronomy & Astrophysics
> j-valdes AT uchicago DOT edu University of
> Chicago
>
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