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Data cartridges on page 178
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Tape drive read or write performance seems slow on page 178
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 & Tape Tools on page 164.
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's 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, in addition to 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.
Backup/archive software and method
Each backup method has its own impact on performance, depending on how well it can keep data
streaming to the tape drive. In most cases, native applications do not have the features required to
maximize performance for LTO tape drives. Hewlett Packard Enterprise recommends using a full-featured
backup or archive application with this library.
Average file size
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