STORE and TurboSTORE/iX Products Manual (B5151-90003)

100 Chapter6
STORE and TurboSTORE/iX Command Options
STORE Options
the total amount of all data written for the backup.
The Throughput section follows the data written columns. The throughput for a particular
piece of media is computed by dividing the total amount of data written for a piece of
media by the time it took to completely write that data. The time required to switch media
is NOT accounted for in this computation. Only time spent actually writing the media is
used. Also, note that if software compression is being used, then the amount of compressed
data written is used to compute the throughput. Your
virtual throughput may actually be
higher, if software compression is used.
The number of hardware retries encountered when writing the data is also displayed here.
This only applied to magnetic tape, DDS, and 3480 media. It has no meaning when writing
to disk files or magneto-optical devices, and will always be zero. Monitoring the number of
retries for a piece of media is important in determining if that media is starting to go bad.
An increased number of retries could indicate that the media should no longer be used, or
that your devices should be cleaned and/or serviced.
After the Throughput section, the total elapsed time for the backup is displayed. This time
does include media switches.
If software compression is used for the backup (with COMPRESS=LOW or COMPRESS=HIGH),
then a section on compression ratios will follow the Throughput section. For each media, or
each media in each parallel set, the amount of uncompressed file data written is displayed
with the amount of data actually written when that file data is compressed. The ratio
between these two numbers and a compression percentage is also displayed. The higher
the ratio is, the better the data compressed. Similarly, the higher the percentage, the
better the data compressed. A negative percentage is possible, and indicates that the data
you were storing did not compress at all. If you see this in your statistics display, or see
very low compression ratios, it indicates that you are storing data that does not compress
well, and that it might be better not to use software compression, or try a different
software compression (LOW instead of HIGH, for example).
NOTE These compression ratios are highly dependent on the type of data being
stored, and may vary from the Hewlett-Packard supplied compression ratios.
In general, data files will compress better than application and system files.
You should carefully pick the type of data compression used to match the type
of data being stored.