HP 3000 Manuals HP 3000 Manuals
Storing Files in Interleave Format (INTER)
With TurboSTORE/iX, you have the capability of simultaneously reading
information from different files on multiple disk drives and storing the
accessed information on the backup device in a single operation.
This process, called interleaving, allows you to match a slow input
device (for example, a disk drive), with a fast backup device (for
example, a streaming backup drive). This effectively increases the input
rate.
By varying the number of concurrent input operations, the effective input
rate can be matched with the output rate. This allows the backup to
execute closer to the speed of the output device.
When you STORE files in interleave format, STORE:
1. Partitions the set of files to your backup device or devices.
2. Opens the files. It may (depending upon file characteristics),
access several files at the same time.
3. Interleaves files on the same backup to make sure that your backup
device or devices operate at the highest speed possible.
Interleave format significantly reduces the time necessary to store a
large set of files, such as when performing a full system backup. It
merges the stream of data from multiple files on separate disks into a
single stream of data sent to the backup device or devices. If
necessary, STORE processes files out of sequence to keep backup devices
operating efficiently.
Interleave format is most efficient when your file set is evenly spread
across two or more system disks. Use sequential devices or parallel
devices alone when the set of files to store is smaller and less evenly
distributed, such as when doing a partial backup, or if the files are
only coming from one disk.
Figure C-4 , "Interleave Tape Format," in Appendix C, "STORE Tape
Formats," illustrates interleave format. To STORE files in interleave
format, use the INTER parameter. For example:
:FILE T;DEV=TAPE
:STORE @.OPERATOR.SYS;*T;INTER
When these files are restored, RESTORE will automatically recognize the
interleave format and restore the files properly.
Using the STORESET and INTER parameters together improves backup time on
large systems. For example, the following STORE command uses both
parallel device pools and interleaving to minimize backup time:
:STORE @.@.@;;SHOW=OFFLINE;&
STORESET=(*T,*T),(*T,*T);INTER