Abstract
This tip discusses IBM Tivoli Storage Manager and open files backup in Windows XP/2000/2003 environments.
Contents
There are two types of open file issues that are related to IBM Tivoli Storage Manager:
In the first issue
The files are opened by application(s), but are available for “read” access by other applications, so that regardless of IBM Tivoli Storage Manager backup copy group serialization setting, IBM Tivoli Storage Manager can backup these files.
However, IBM Tivoli Storage Manager’s STATIC and SHRSTATIC serialization settings will prevent backup of files or directories being modified during the backup process, while IBM Tivoli Storage Manager’s DYNAMIC and SHRDYNAMIC serialization settings allow this kind of backup (“fuzzy” backup).
A fuzzy backup means that the files or directories were 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 files or directories and could be useless for applications, such as databases, because a restore would yield inconsistent databases. In this case, you should consider using IBM Tivoli Storage Manager for the databases module that is designed to provide consistent online backup of databases.
Therefore, DYNAMIC and SHRDYNAMIC serialization settings should be used with caution and only for those cases where the restore of a “fuzzy” backup will result in usable files or directories.
Here are all possible IBM Tivoli Storage Manager backup copy group serialization setting definitions:
- SHRSTATIC specifies that a file or directory must not be backed up while being modified. Tivoli Storage Manager attempts to perform a backup as many as four times (default value), depending on the value specified for the CHANGINGRETRIES client option.
- STATIC specifies that a file or directory must not be modified during backup. If a file or directory is modified during the backup attempt, it is not backed up. Tivoli Storage Manager attempts to perform the backup only once.
- SHRDYNAMIC specifies that if the file or directory is being modified during a backup attempt, Tivoli Storage Manager backs up the file or directory during the last attempt even though the file or directory is being modified. Tivoli Storage Manager attempts to perform a backup as many as four times (default value), depending on the value specified for the CHANGINGRETRIES client option.
- DYNAMIC specifies that a file or directory is backed up on the first attempt by Tivoli Storage Manager, regardless of whether the file or directory is being modified during backup processing.
In the second issue
The files are opened by an application for exclusive use, therefore unavailable for “read” access by any other applications including IBM Tivoli Storage Manager. In this case, there are several possible approaches to circumvent this situation:
- If possible, shutdown the application(s) before performing backup and start the application(s) again once backup has finished. IBM Tivoli Storage Manager provides PRESCHEDULECMD and POSTSCHEDCMD options to automate this process.
- Use the product to manage open files and eliminate the “fuzzy” backup issue. It not only permits access to “locked” files but also presents a consistent image of the files to IBM Tivoli Storage Manager. That is, even if the file changes during backup, open file manager presents IBM Tivoli Storage Manager with the unchanged version of the file, so a consistent backup is always taken. However, open file manager will not capture and backup applications’ data cached in memory, so that even “good” backups are obtained by using open file manager - and when restored, may not represent the true state of data.
St. Bernard Software’s “Open File Manager” has integration with Tivoli Storage Manager. For more information, see http://www-306.ibm.com/software/tivoli/partners/public.jsp?tab=connect&content=rft-validation-tsm and http://www.stbernard.com/products/ofm/products_ofm.asp. - IBM Tivoli Storage Manager Windows Client Version 5.1 introduced a Logical Volume Snapshot Agent (TSMLVSA.SYS) to enable online image backups for Windows 2000/XP. The Version 5.3.2 Windows Client added Windows 2003 support for the LVSA. This file is a Windows Driver Model (WDM) device driver and is loaded as an upper filter for each local volume on the machine. By activating this agent on a Windows 2000/2003/XP machine, online image backups can be performed on any logical volume (partition) basis.
Logical Volume Snapshot Agent does not capture and backup applications’ data cached in memory, so in this case, it presents the same limitation as the open file manager product.
More information can be found in the manual IBM Tivoli Storage Manager for Windows Backup-Archive Clients Installation and User’s Guide, GC32-0788.
(http://www.elink.ibmlink.ibm.com/public/applications/publications/cgibin/pbi.cgi?CTY=US&FNC=SRX&PBL=GC32-0788-05) - Use additional IBM Tivoli Storage Manager modules such as IBM Tivoli Storage Manager for Databases, IBM Tivoli Storage Manager for Enterprise Resource Planning, IBM Tivoli Storage Manager for Mail or IBM Tivoli Storage Manager for Application Servers to provide consistent online backup of specific applications’ databases.
More information about each module can be found at: http://www.ibm.com/software/tivoli/solutions/storage
Special Notices
This material has not been submitted to any formal IBM test and is published AS IS. It has not been the subject of rigorous review. IBM assumes no responsibility for its accuracy or completeness. The use of this information or the implementation of any of these techniques is a client responsibility and depends upon the client's ability to evaluate and integrate them into the client's operational environment.