HP StoreEver Ultrium Tape Drives - Manual (Page 10)

for example, through an unplanned power outage or accidental unplugging, the volume will be
left in an inconsistent state, and all files added since the last dismount operation will be inaccessible.
The CheckWizard utility may be able to recover the file data to the _ltfs_lostandfound
directory, but the metadata (filename, access dates, and so on) will be lost.
The final mechanism provided in HP StoreOpen Standalone is to update the index every time a
file is closed after writing. This further reduces the exposure window to a single file, or (if several
processes are using the volume simultaneously) to the number of files being written concurrently.
However, this does add some overhead, both in terms of the tape capacity used for each index,
and also in terms of performance since the writing of the index will take bandwidth away from
writing data. These overhead effects will become more severe with smaller file sizes.
In most cases the default behavior offers the best solution, but the options allow you to modify the
behavior for a particular situation. The following table summarizes the options available for choosing
when the index is updated:
Potential drawbacks Potential benefits Index is flushed to tape...
Exposure to the risk of power failure
during writing. Minimal capacity overhead. When the volume is unmounted.
Some capacity overhead since the
index is written more frequently. Exposure to the risk of power failure,
limited to the last n minutes. Every n minutes during writing
(default: n=5).
Negligible impact on performance.
Greater capacity and performance
overhead, especially if writing small
files. Exposure to the risk of power failure
is limited to a single file (more if
several processes are writing to
different files concurrently). When any file open for writing is
closed.
Cartridge utilities
The cartridge utilities button opens a further window where you can access the utilities for formatting
the tape, etc.
•
Load: Physically loads the tape which is already presented to the drive.
•
Unload: Physically ejects the LTFS volume from the tape drive. The file system will continue to
run, but attempting to access the volume while no cartridge is present will result in the error
10 Using HP StoreOpen Standalone