BacPac is fast backup software for OpenVMS VAX, Alpha, and Integrity )Itanium IA64) platforms. Combining state of the art file compression technology, client/server architecture, and network communications, BacPac provides full and incremental backups in 1/2 the time, creates savesets in 1/2 the space, and provides for remote backups. BacPac's data compression techniques are based on years of research and in use on thousands of VAX and Alpha systems worldwide:

• Reduce the number of tapes required for a backup, or the amount of disk space for a disk saveset
• Speed up the backup by 2 to 1

Not only does BacPac reduce the number of tapes required for a backup, the entire operation is speeded up. Compression and I/O are overlapped to maximize throughput to the tape device. Comparison tests show that BacPac is up to three times as fast as VMS BACKUP.

BacPac is a powerful backup utility which provides all the standard modes of operation:

• Image mode save and restore of complete disks
• Incremental and differential save and restore of changes to disks
• Standalone operation save and restore of system disks
• Selective restore of individual files

Remote Backup

BacPac's new client/server architecture provides for backup of local disks to remote tape drives and or disks, as well as backup of remote disks to local tape drives or disks. Both image and incremental mode are supported. All other BacPac options are also supported including listing of remote tapes, selective restore of files from remote tapes to local disks, and restore of files from local tapes to remote disks.

All data is transferred from node to node in compressed form using DECnet. This means that only half the data is actually transferred thus providing the same speed improvements as local BacPac.

Throughput

Optionally, all data written to and read from tapes (and across the network) is in compressed format. Typical compression ratios range from 2:1 to 5:1 or a net reduction of 50% to 80%. This results in substantially less data being sent to the tape drive, which, being the slower device, increases the overall throughput. For example, if a tape drive is rated at 500KB per second with uncompressed data, the throughput is limited to 500KB. However, if the data is compressed first and the resulting ratio is 3:1 then each block of data sent to the tape drive is actually three disk blocks resulting in an effective throughput of 1500KB per second.

Saving Disks

BacPac provides the capability to create complete image copies of individual disks. In this mode, all files on the disk are saved including lost files (those not belonging to a directory) and information about alias files and directories. Volume information required to logically restore the disk to its original state is also saved. The image mode save operation is supported in both the online (both local and remote) and standalone environments.

Saving Files

Incremental saves of selected files can be used to supplement complete image saves but on a more frequent basis. Typically, image saves are done once a week or maybe once a month with incremental saves being done on a daily basis selecting only those files created or modified since the last image save.

Files can also be archived by saving selected files and then deleting the saved files. Archiving files is used to free up disk space used by files which are not being accessed but may be needed at some time in the future.

Restoring Disks

Files that were saved during an image save operation can be restored either as part of a complete restore of the disk (image restore) or by selecting specific files to be restored (selective restore).

The image restore operation restores a complete disk to a logical equivalent of the original disk. All of the files are restored to their original state except that they are made virtually contiguous during the restore. This has the effect of defragmenting the files on the disk. While defragmentation utilities perform a useful function in maintaining a disk, there are certain files which they cannot defragment; BacPac will defragment all of the files on a disk during the restore operation.

Restoring Files

BacPac provides the capability to retrieve one or more files which were written to tape during an image or an incremental save operation. Files which have inadvertently been deleted or which have been archived can be quickly restored using the selective restore operation.

Disk Duplication

BacPac performs full image copies of disks from one VMS system to another without requiring that the systems be clustered. The copied disks are duplicates of the original disks and are available for use as soon as the copy completes.

BacPac provides added backup safety by optionally creating a saveset backup of the source disk at the same time as the disk copy is being made.

GENERAL FEATURES

• Image mode save operation saves all files on disk including files with lost file headers and alias file/directory information
• Image mode restore initializes the disk including checking for bad blocks and rebuilding the storage bit map
• Image mode restore maintains complete file integrity including preserving the original file ID
• Compression algorithms in use at thousands of VAX/AXP sites worldwide since 1988
• Reduces saveset size written to tape or disk by 50% to 80%
• Saveset verification using CRCs on a per file basis
• Multiple tape volumes including OPCOM messages; cascading is also supported
• Full logging and reports including list, error logs, and statistics
• Journal files
• Selective restoration of files from either incremental saveset or image mode saveset
• Ability to software write lock a disk during an image save operation
• Broadcast messages to users at start and end of BacPac operations
• Disk duplication copies a disk over a network between non-clustered systems
• Disk duplication can keep an optional saveset in addition to copying a disk
• Optional MAIL notification upon completion of a BacPac operation

 

TECHNICAL DESCRIPTION

Image Mode Operation

During an image save operation, all files on the disk are saved. All of the information necessary to restore each file to its current state is saved with the file. In addition, information about the structure of the volume is also saved, e.g., boot block, home block, number of file headers allocated, etc.

An image restore recreates a logically equivalent copy of the original disk. A logical copy of the disk is one which contains all of the original files with all their original attributes including the original file IDs but does not maintain the original placement of blocks on the disk. The disk is first initialized: by default, the parameters from the saved disk are used.

Optionally the disk may be initialized first and the parameters from this initialization used. Files are then restored with all their original attributes. Files with placement criteria are supported. Files which are 'lost', i.e., do not belong in a directory are also restored. Alias files and directories are reconstructed.

A disk recreated from an image restore operation will have all of the files logically contiguous; this does not mean that files will be marked as contiguous, only that they have been effectively defragmented.

Incremental Mode

An incremental save operation provides the capability to save files selected by any one of the four dates (BACKUP, CREATED, EXPIRED, MODIFIED) associated with a file and by the file name. All wildcards are supported. Files may be specifically excluded from an incremental save operation. In all cases, all of the information necessary to restore the file to its current state is saved with the file.

Selective Restore Operation

The selective restore operation recreates a virtually equivalent copy of the original file. A virtually equivalent copy is one which contains all of the original data of the file and all of the original attributes of the file except those attributes specifically overridden. In addition, the original file ID and the original placement of blocks for the file are not preserved. Files selectively restored can be restored to different file names, a different directory tree, and even to a different disk. If the original file was marked as contiguous, then it will be restored and marked as contiguous. If there are insufficient contiguous free blocks to restore the file then the file will not be restored unless the user specifically overrides this during the restore.

Logging and Reports

The list operation provides the capability to display the contents of BacPac saveset files. Summary, brief and detailed display formats are available. The output can be directed to a file on any node or to the user's terminal. The display output can be controlled to only display selected files, only those files which are open, or all files which are processed.

Journal files may be created or appended to (on any node) with the online save operation, providing an ongoing journal of all files backed up. The list operation is used to display the contents of a journal file.

Error logs are created automatically if errors are detected during an online save or restore operation. All errors reported, as well as the date of execution and the command line used, are included.

BacPac (local and remote) provides statistics at the completion of operation. The statistics include elapsed time, CPU time, and compression rate for a save operation.

Tape Security

BacPac supports normal tape label processing which precludes writing to the wrong tape unless specifically overridden. The specific items checked include:

• Tape label
• Tape expiration date
• Accessibility field
• VMS protection code

In addition, the user can specify any of these items on the command line and may also override checking of these items.

Disk Security

During an image mode restore operation, the disk being restored is required to be mounted foreign. The user must have the privilege to mount the disk as foreign before BacPac even executes. Normal VMS file protection is used during other online operations.

Hardware/Software Requirements

BacPac will run on the following VMS systems:

• VAX running VMS version 5.5 or later
• Alpha running OpenVMS version 6.2 or later
• Integrity (Itanium IA64) running OpenVMS Version 8.2 or later.