The problem could lie with the drive:
1.
Check the cables and connectors.
2.
Clean the tape heads with the cleaning cartridge.
3.
If the problem persists, check the environmental conditions against the specified limits, see (page 29). Perhaps move
the drive to a more suitable site.
Has a new operating system been installed in the host computer? Has new backup software been installed?
The problem could lie with the host or the software. Consult the computer's operating manuals, the software manual, or
seek help from a service engineer.
Optimizing performance
Various factors can affect tape drive performance, particularly in a network environment. In nearly all cases when performance
is not as expected, it is the data rates of the disk subsystem that cause the bottleneck.
If your tape drive is not performing as well as expected—for example, if backup windows are longer than expected—please
consider the following points before contacting Customer Support.
Can your system deliver the required performance?
•
The LTO–6 tape drive can write uncompressed data at up to at up to 160 MB/sec (576 GB/hour).
•
The LTO–5 tape drive can write uncompressed data at up to 140 MB/s (504 GB/hour).
•
The LTO–4 tape drive can write uncompressed data at up to 80 MB/s (288 GB/hour).
•
The LTO–3 tape drive can write uncompressed data at up to 60 MB/s (216 GB/hour).
To obtain this performance it is essential that your whole system can deliver this performance. In most cases, the backup
application will provide details of the average time taken at the end of the backup.
Typical areas where bottlenecks can occur are:
•
Disk subsystem
A single-spindle disk will not be able to deliver good data throughput at poor compression ratios. Best practice to
ensure good throughput is to utilize multiple disk spindles or data sources.
•
System architecture
Be aware of the architecture of your data protection environment.
The aggregation of multiple client sources over a network provides a good way of delivering good performance, but
anything less than Gigabit Ethernet will limit performance for LTO tape drives.
Some enterprise class backup applications can be made to interleave data from multiple sources, such as clients or
disks, to keep the tape drive working at optimum performance.
•
Tape media type
The data cartridge should match the specification of the tape drive. A lower specification will have a lower transfer
speed (see Data cartridges (page 25)). Use:
◦
Ultrium 6.25 TB R/W or Ultrium 6.25 TB WORM cartridges with LTO–6 tape drives
◦
Ultrium 3 TB R/W or Ultrium 3 TB WORM cartridges with LTO–5 tape drives
◦
Ultrium 1.6 TB R/W or Ultrium 1.6 TB WORM cartridges with LTO–4 tape drives
◦
Ultrium 800 GB R/W or Ultrium 800 GB WORM cartridges with LTO–3 tape drives
•
Data and file types
The type of data being backed up or restored can affect performance. Typically, small files incur greater overhead in
processing and access than large files. Equally, data that is not compressible will always limit the speed at which the
drive can write/read data. You will achieve no more than native rates with uncompressible data.
30
Troubleshooting
