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on page 160
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Backup/archive software and method
on page 161
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Connection from the archive/backup host server to the library
on page 161
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on page 161
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Tape drive read or write performance seems slow
on page 161
You can use the L&TT system performance test to assess the performance of simulated backup and restore
operations. For information on downloading and using L&TT, see
Diagnosing problems with Library &
Average file size
The hard drive must seek to the position of a file before it can start reading. The more time the disks are
seeking to files, the lower the performance. Therefore, if the average file size is small, the read performance
will be lower.
To determine the average file size, divide the size of the backup by the number of files.
If the average file size is small (64 KB or less), consider using a sequential, image, or block backup method
that backs up the whole hard drive or LUN image instead of individual files. The trade-off for using one of
these methods is that you might only be able to restore the entire image instead of individual files.
NOTE:
File fragmentation will also cause excessive drive seeking, which lowers performance, so ensure that files are
regularly defragmented.
File storage system
The file storage system determines the organization of the files on the disks. Using RAID controllers to spread
files over multiple disks can improve performance because some disks can be seeking while others are
reading. Storing files on a single non-RAID disk results in the slowest performance while storing files on a
high-end disk array results in the fastest performance.
Converting standalone disks to RAID can improve performance.
Ensure that the file systems being backed up have no or minimal fragmentation.
Connection from the backup server to the disk array
The connection between the host server and the disks determines how much data can be transferred from the
disks to the host computer at a time. A connection with insufficient bandwidth cannot provide enough data for
the tape drives to write at full speed. For optimum performance, the storage subsystem must be able to
provide data at the tape drive maximum transfer rate.
Backup systems using a lower speed Ethernet network should use multiple network connections.
Backup/archive server
The backup server must have enough RAM and processor power to transfer the files from the disk to the tape
drive while also running the backup or archive software and any other processes.
Check the RAM and processor usage during a backup operation. If they are operating at capacity, adding
RAM or processor capability can improve performance.
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Average file size
