Conducting a performance assessment of drives – HP StoreEver Ultrium Tape Drives User Manual
Page 22
NOTE:
You can obtain additional help by hovering your mouse cursor over the appropriate field
and/or clicking on Help.
Conducting a performance assessment of drives
Conducting a performance assessment of tape drive is important because:
•
HP’s Ultrium tape drives are extremely fast, and if you utilize them at the fastest transfer rates,
backup windows will be shorter, making better use of the equipment.
•
If the drives are not kept streaming, drive life may be limited by reposition life. This could result
in premature drive retirement.
1.
Once the first backup is complete, HP TapeAssure generates performance data to view. Select
Drives -> Performance from the Navigation pane.
2.
Check the Media Transfer rate.
Also known as the native transfer rate, this is the rate at which the drive writes data to the tape
after compression. If the drives are being used at their maximum speed, then this rate will line
up with the native speed specifications for the drive. If the drive is not operating at its maximum
media transfer rate, then there is a potential opportunity to make better use of the drive’s
performance.
3.
Check the Estimated Host Transfer Rate to see what data rate the drive is experiencing from the
host.
This is the media transfer rate multiplied by the compression ratio, but it is useful to know the
data rate from the host point of view. This is the actual data rate of the data being received from
the host to the drive and is the rate most under your control.
4.
If these data rates are lower than expected, the data from this screen give you the evidence
needed to examine the data path between the source data and the host interface of the drive.
There is nearly always a significant opportunity to make better use of the high data rates the tape
drives can accept, though the solution is not necessarily straight forward. Bottlenecks could be
caused by:
• The source disks
• The SAN
• The host server
• The host bus adaptors (HBAs), or other devices consuming bandwidth etc.
Using TapeAssure
22