Performance Assessment Tools
NOTE:
We strongly reco
mmend that you check the information on our web site at h
ttp://www.hp.com/support/
pat.Thisconta
ins d etailed support information that will enable you to identify bottlenecks and take full
advantage of the performance capabilities of the Ultrium family of tape drives.
You can use our free, standalone per formance assessment tools to check tape per formance and test
whether your disk subsystem can supply data at the maximum transfer rate.
Thetoolsarelocatedonlineath
ttp://www.hp.com/support/p at. They are also integrated into HP
Library & Tape Tools, which is available both online (h
ttp://www.hp.com/support/tapetoo ls)and
on the CD-ROM supplied with your tape drive.
Optimizing performance
Various factors can affect tape drive per formance, particularly in a network environment. In nearly all
cases when performance is not as expected, it is the da ta 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 tr y the tools and consider the following points before contacting HP Support at
h
ttp://www.hp.com/support.
Can your system deliver the required performance?
• The Ultrium 1760 tape drive can write uncompressed data a t up to 80 MB/s (288 GB/hour) or
compressed data at up to 160 MB/ s (576 GB/hour), assum ing 2:1 compression.
• TheUltrium920tapedrivecanwriteuncompresseddataatupto60MB/s(216GB/hour)or
compresseddataatupto120MB/s(432GB/hour),assuming2:1compression.
• The Ultrium 448 tape drive can write uncompressed data at up to 24 MB/s (86 GB/hour) or
compresseddataatupto48MB/s(172GB/hour),assuming2:1compression.
To obtain this per formance i t 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 b ottlenecks can occur are:
• Disk subsystem
A single spindle disk may not be able to deliver good d ata throughput at poor compression
ratios.Bestpracticetoensuregoodthroughputistoutilizemultiplediskspindlesordatasources.
• System architecture
Be aware of the architecture of your data protection environment.
The ag gregation of multiple client sources over a network provides a good way of delivering good
performance, but a nything less than Gigabit Ethernet will limit performance for Ultrium 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 t ype
The data cartridge should match the specification of the tape drive. A lower specification will
have a lower transfer speed (see “Data cartridges”onpage59). Use:
• Ultrium 1 .6 TB R/W or Ultrium 1.6 TB WORM cartridges with Ultrium 1760 tape drives
• Ultrium 800 G B R/W o r Ultrium 800 GB WORM car tridges with Ultrium 920 tape drives
• Ultrium 400 GB R/W cartridges with Ultrium 448 tape drives
• Data and file types
The t ype of data being backed up or restored can affect p er formance. Typically, small files incur
greater overhead in processing and access than large files. Equally, data that is not co mpressible
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Diagnostic Tools and Performance
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