Technical data

Using BACKUP
11.15 Backing Up User Disks
2. You can also specify multiple disk drives as the output device in the BACKUP
command line. For example:
$ MOUNT DUA0: USER1
%MOUNT-I-MOUNTED, USER1 mounted on _DUA0:
$ MOUNT/FOREIGN DUB24:
%MOUNT-I-MOUNTED, DISK2 mounted on _DUB24:
$ MOUNT/FOREIGN DUB25:
%MOUNT-I-MOUNTED, DISK3 mounted on _DUB25:
$ BACKUP/RECORD/SINCE=BACKUP
_From: DUA0:[000000...]
_To: DUB24:USER1.SAV,DUB25/SAVE_SET
11.15.6 Performing Incremental Backups Using PATHWORKS for OpenVMS
Servers
An incompatibility between the operating procedures of the PATHWORKS for
OpenVMS Macintosh server and OpenVMS incremental backup operations
can cause BACKUP to save entire disks or directory structures, including
subdirectories and files.
BACKUP can detect whether a directory file has been modified since the date
indicated by the Backup Date field in the file header. If a directory file has been
modified, all subdirectories and files of that directory are saved for possible later
restore operations.
Updating the modification date of directory files is unusual for OpenVMS
systems. However, it can happen if, for example, you rename a directory file
from one location to another. In contrast, the PATHWORKS Macintosh server
maintains the modification date of directory files for Macintosh users; that is,
it updates the modification date for each directory change, file creation, and file
deletion.
Thus, an incremental backup of a disk where PATHWORKS is used to serve
files to Macintosh users may result in saving the entire disk or entire directories
(including their subdirectories and files) instead of just the user files that were
created or modified since the last incremental backup operation.
You can avoid saving files unnecessarily in either of the following ways:
• By using the /NOINCREMENTAL qualifier.
On a save operation, you can use the BACKUP qualifier /NOINCREMENTAL
to avoid saving all the files and subdirectories under directories that have
been modified. (Some files will, however, still be saved.) Use this qualifier
only if you are sure that you do not want to save all data.
Prior to OpenVMS Version 6.2, the system, by default, did not save the files
and subdirectories that were under directories that had been modified. In
OpenVMS Versions 7.0 and 7.1, to ensure a successful restore, the system
saved all files and subdirectories under directories that had been modified.
This behavior, however, sometimes resulted in saving files and subdirectories
that were not needed for later restore operations. The /NOINCREMENTAL
qualifier allows you more control over the amount of file data that is saved.
• By performing a ‘‘dummy’’ BACKUP/RECORD operation on all directory files
immediately before performing the incremental backup. For example:
11–38 Using BACKUP