PRIMECLUSTER Global File Services Configuration and Administration Guide 4.2 (Solaris(TM) Operating Environment)

24.2.3 Notes on using differential backup

sfcdump(1M) provides the differential backup function that backs up only files updated after the last backup. This manual does not describe a specific procedure for differential backup.

Note the following when using differential backup.

24.2.3.1 The node that performs the differential backup

Differential backup is implemented by using the dump record file (/etc/sfcfs_dumpdates) information updated through sfcdump command execution with the u function modifier specified. Only dump record files on the node that executed sfcdump are updated, therefore, differential backups must always be performed from the same node.

If a differential backup is to be performed from another node, the dump record file must be copied from the node where backup was previously performed.

24.2.3.2 If a panic occurs on a node

A differential backup of a GFS Shared File System may not properly backup files updated from a node that did not stop normally, for example due to a panic.

sfcdump(1M) determines whether to backup files during a differential backup by comparing the time information of files and the time when backup was last performed as obtained from the dump record file. If a node does not stop normally, the contents of files may be updated without the time information of the files being updated. Such files will not be backed up by a differential backup. They may not be backed up until the next full backup.

If a node using the GFS Shared File System has failed to stop normally, the next backup should be a full backup.