Backup versions of files with time stamps prior to January 1970 or after February 2106 are subject to premature expiration
The IBM Spectrum Protect backup-archive client and the IBM Spectrum Protect for Space Management client can incorrectly store atime, mtime, or ctime time stamps of files on the IBM Spectrum Protect server if the time stamp is earlier than January 1, 1970 or later than February 7, 2106. This can lead to premature expiration of backup versions of an affected file. If an affected file is migrated, the subsequent backup or archive operation will prematurely recall the file data. If an affected file is restored or retrieved by the backup-archive client, or recreated by dsmmigundelete, then the affected time stamps in the file differ from the original time stamps.
- During incremental backup operations, affected files are always backed up, even if they have not changed. When the number of backup versions exceeds the VEREXISTS setting of the management class's backup copy group, then the oldest backup version expires. Thus if a file has not actually changed, but is backed up anyway, this behavior can lead to premature expiration of the file's backup versions.
- When an affected file is restored or retrieved by the backup-archive client, or recreated by dsmmigundelete, then the affected time stamps differ from the original (correct) time stamp. Although a time stamp is not part of the file's content, certain applications might not function correctly if the time stamps are wrong. For example, IBM Spectrum Protect for Space Management and Tivoli Storage Manager for Space Management use the file's last access time (atime) to determine when files are eligible for migration to lower-tier storage. Incorrect time stamps can lead to either premature or delayed migration of data. The file content is not lost, but this is an example of how time stamp integrity can impact other operations or applications.
Required conditions for this problem to occur
- The file resides on an AIX, Linux, or macOS file system that is not IBM Spectrum Scale ("GPFS"). Files on GPFS are not affected because GFPS does not support time stamps earlier than January 1, 1970 12:00:00 AM GMT, or later than February 7, 2106 6:28:15 AM GMT.
- The file's atime, ctime, or mtime time stamp is earlier than January 1, 1970 12:00:00 AM GMT, or later than February 7, 2106 6:28:15 AM GMT.
- The file is bound to a management class whose backup copy group is configured with a VEREXISTS value other than NOLIMIT. Premature expiration of backup cannot occur when VEREXISTS is set to NOLIMIT.
- IBM Spectrum Protect Backup-Archive Client for UNIX and Linux (including macOS) versions 8.1.x
- IBM Spectrum Protect for Space Management version 8.1.x
- IBM Tivoli Storage Manager Backup-Archive Client for UNIX and Linux (including macOS) versions 7.1.x and earlier
- IBM Tivoli Storage Manager for Space Management version 7.1.x and earlier
a. Create two test files that have modification dates of December 31, 11:59:59 GMT and February 7, 2106 6:28:15 AM GMT, respectively. Note that the touch commands use the local time, and the following examples are based on a local time of GMT-05:00 hours (US Eastern Time):
touch -m -t 210602070128.15 it28106_max touch -m -t 196912311859.59 it28106_min
b. Use the find command to identify files with affected atime, ctime, or mtime values:
find / ! -newer /it28106_min -or -newer /it28106_max -or ! -cnewer /it28106_min -or -cnewer /it28106_max -or ! -anewer /it28106_min -or -anewer /it28106_max
- IBM Spectrum Protect Backup-Archive Client 188.8.131.52. Current target availability is June 2019.
- IBM Tivoli Storage Manager Backup-Archive Client 184.108.40.206. Current target availability is July 2019.
Related informationAPAR IT28106
|Tivoli Storage Manager||Backup-Archive Client||AIX, HP-UX, Linux, Mac OS, Solaris||All Versions|
|IBM Spectrum Protect for Space Management||AIX, Linux||All Versions|
|Tivoli Storage Manager for Space Management||AIX, Linux||All Versions|
More support for:
IBM Spectrum Protect
Component: Backup-Archive Client
Software version: All Versions
Operating system(s): AIX, HP-UX, Linux, Mac OS, Solaris
Reference #: 0883238
Modified date: 07 June 2019