HP EH920A - StorageWorks Ultrium 1760 Tape Drive, Руководство пользователя

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• The HP StorageWorks Ultrium 448c Tape Blade can write uncompressed data at up to 24 MB/s
(86 GB/hour).
If your tape blade is not performing as well as expected—for example, if backup windows are longer
than expected—please try the tools and consider the following points before contacting HP Support at
http://www.hp.com/support .
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 in a RAID
con fi guration or use multiple 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.
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. The drawback
of interleaving is that it will increase the time needed to restore data.
• Tape media type
The data cartridge should match the speci fi cation of the tape drive. A lower speci fi cation will
have a lower transfer speed (see “ Data cartridges ” on page 39). Use
• Ultrium 1.6 TB cartridges with the HP StorageWorks SB1760c Tape Blade
• Ultrium 800 GB cartridges with the HP StorageWorks SB920c Tape Blade
• Ultrium 400 GB cartridges with the HP StorageWorks Ultrium 448c Tape Blade.
• Data and fi le types
The type of data being backed up or restored can affect performance. Typically, small fi les incur
greater overhead in processing and access than large fi les. 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.
Examples of fi les that compress well are plain text fi les, spreadsheets; those that compress poorly
are those that are either compressed as part of their format (such as, JPEG photographic fi les) or
stored as compressed (such as, .ZIP fi les or .gz/.Z fi les on Unix platforms).
Problems with cartridges
If you experience any problems using HP branded cartridges, check:
• You are using an Ultrium cartridge. Compatible media can be recognized by the Ultrium logo,
which is the same as the logo on the front of your drive.
• You are using the correct media type: Ultrium 1.6 TB* tape cartridges (C7974A or C7974W) for
use with HP StorageWorks SB1760c Tape Blades; Ultrium 800 GB* tape cartridges (C7973A or
C7973W) for use with HP StorageWorks SB920c Tape Blades; Ultrium 400 GB* tape cartridges
(C7972A) for use with HP StorageWorks Ultrium 448c Tape Blades.
• If you are using C7974W or C7973W tape cartridges with the HP StorageWorks SB1760c or
SB920c Tape Blade respectively, remember that you can only write to these cartridges once.
• The cartridge case is intact and that it contains no splits, cracks or damage.
• The cartridge has been stored at the correct temperature and humidity. This prevents
condensation. See the insert included with the tape cartridge for storage conditions.
• The write-protect switch is fully operational. It should move from side to side with a positive click.
• The World Wide Web site for more detailed troubleshooting information:
http://h18004.www1.hp.com/products/blades/components/c-class-storageworks.html .
The cartridge is jammed
If the cartridge is jammed or the backup application is unable to eject it, you can force eject the
cartridge. Once the cartridge is successfully ejected, it is good practice to run Library & Tape Tools to
Tape Blade
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