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• The margin assessment, rather than the reported temperature
• Over temperature (or under) will be highlighted
Drive performance
The Drive Performance section shows performance-related measurements for the drive base on the
current and up to four previous tapes.
Figure 24 Support ticket Drive Performance section
• Estimated native data rate – this is the rate after compression and so should be compared
with the native data rate of the drive (which is shown in this section) rather than the host rate.
It is an estimate but should be accurate to within 10% as long as the amount of data is at least
1 GB. The rates shown here will be the approximate host rate divided by the compression
ratio (which is not known for previous tapes) but this can still give a very good idea of whether
the transfers are host limited or drive limited. LTO drives have very high native transfer rates
so anything unexpectedly slow is most likely to be caused by the host or, more likely, the
sourcing of the data. Even a drive that is struggling will operate at more than 50% of its native
transfer rate.
• Specified max native data rate – this is a constant for each drive type.
• Max data rate achieved – this is an internal measure on the entry to the compression engine.
This is the highest data compression rate. but only very high compression ratios are likely to
result in this being a bottleneck.
• Compression ratios – only available for the current tape but can be used as an indicator for
backups/restores in general as long as the type of data is similar
When troubleshooting, check for:
• Slow transfer rates caused by the host/source data IO
Drive usage
The Drive Usage section shows lifetime usage measurements for the drive.
Understanding LTO support tickets 85