There are two variants on open file issues that are pertinent to TSM:
1) The file is open by an application, but is available for "read" access
by other applications (such as TSM). Regardless of the TSM copy group
serialization setting, TSM can back up these files. The serialization
setting affects how TSM handles cases where the file has changed in the
middle of backing up the file. STATIC and SHRSTATIC will not store a
backup copy on the TSM server if the file changed in the middle of the
backup. DYNAMIC and SHRDYNAMIC will allow a backup copy of the file to be
stored on the TSM server even if the file has changed in the middle of the
backup.
When the file has changed in the middle of the backup, then the backup
copy is often called a "fuzzy" backup. Thus DYNAMIC and SHRDYNAMIC will
permit fuzzy backups to be stored on the TSM server.
Consider: A fuzzy backup means that the file was in one state when the
backup started, but in another state by the time the backup finished. As a
result, the backup copy may represent an inconsistent state for the file.
For certain files, such as message logs that gets appended with new
messages on a regular basis, a fuzzy backup may not be a problem. For
other files, such as databases, a fuzzy backup could be useless since a
restore of this backup would yield an inconsistent database.
Therefore, DYNAMIC or SHRDYNAMIC should be used with caution, and only for
those cases where you KNOW that restore of a fuzzy backup will result in a
usable file. For any file that you are unsure of, consult the owner of the
file or the vendor whose application uses that file to determine the
backup requirements.
St. Bernard's "Open File Manager" can eliminate fuzzy backup issues
because it not only permits access to "locked" files (see #2 below), but
it also presents a consistent image of the file to TSM. That is, even if
the file changes during the backup, Open File Manager presents TSM with
the unchanged version of the file, so a consistent backup is always taken.
2) The file is open by an application for exclusive use, and is therefore
unavailable for "read" access by any other application (i.e. the file is
"locked"). TSM can not back up files that are locked by another
application unless a product to manage open files (such as St. Bernard
Software's "Open File Manager") is used. If someone told you otherwise,
then they are wrong: TSM can not open locked files without Open File
Manager (or similar product) regardless of the serialization setting.
Whether you require Open File Manager depends on your situation. In some
cases, you can use the TSM PRESCHEDULECMD option to shut down applications
that locks certain files before the backup starts. After the backup is
complete, you can use the TSM POSTSCHEDULECMD option to restart the
applications that lock the files.
In other cases, you may not care if TSM can back up the file. One trivial
example is the Windows pagefile.sys file. With a product like Open File
Manager, you could back up pagefile.sys. However, there is no point in
doing so since there is never any need to restore pagefile.sys.
As to whether you need a product like Open File Manager... well, there is
no simple "yes" or "no" answer. Most customers run TSM successfully
without Open File Manager. You should evaluate your particular situation,
i.e. use SHRSTATIC serialization, then see which files can not be backed
up because they changed during backup, or were locked. Review these
exceptions and evaluate your options for handling them. For some files,
you may not care whether they get backed up. For files that changed during
backup, determine whether DYNAMIC or SHRDYNAMIC would be appropriate, or
whether you can shut down the application that uses the files before
running the backup. For files that are locked but need backup, determine
whether you can shut down the application that uses the files before
running the backup. In the case of mission critical files for which none
of these options is viable, you may need to consider using Open File
Manager.
Regards,
Andy
Andy Raibeck
IBM Software Group
Tivoli Storage Manager Client Development
Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
Internet e-mail: [EMAIL PROTECTED]
The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.
William SO Ng/Hong Kong/IBM@IBMHK
Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]>
12/31/2001 00:39
Please respond to "ADSM: Dist Stor Manager"
To: [EMAIL PROTECTED]
cc:
Subject: Open file for TSM
Hello there,
I think this question had been asked before a thousand times but being a
new member to TSM, I'll still confused.
TSM does not has open file option and recommend to use Open File Manager
from St. Bernard Software to back up open file on NT. My question is:
Does this means that TSM must use Open File Manager for a complete backup
solution on NT ?
The official answer from TSM is that we can use dynamic backup to backup
file even if it is locked. But the result will not be guarentee. Does
it
means that we have to use Open File Manager to compensate it ? Does
anyone
use TSM alone and encounter problem on NT platform for open file ?
If the answer for the second question is no, then this Open File Manager
seems to be little of use.
Regards
William
Tivoli Software, IBM Software Group, IBM China/Hong Kong Limited
11/F, PCCW Tower, Taikoo Place, 979 King's Road, Hong Kong
Internet : [EMAIL PROTECTED]
Tel: 2825-7613 Fax: 2825-0022
