US Robotics 7931 Guide de l'utilisateur télécharger pdf (Page 105)

Chapter 3 Archiving 81

Assume that a patient is in the hospital for four weeks. During this time, all of this

patient’s files are on fast media (copy 1=mo). After four weeks, the patient is released

from the hospital. If no data has been accessed for this patient for up to 60 days after

the patient is released, the copy 1 entry in the inode is unarchived, and only copy 2

and copy 3 entries are available. The volume can now be recycled in order to make

room for more current patients without having to increase the disk library. If the

patient comes back to the hospital after six months for follow-up care, the first access

of the data is from tape (copy 2). Now the archiver automatically creates a new copy

1 on disk to ensure that the data is back on the fast media during the follow-up,

which could take several days or weeks.

Controlling How Archive Files Are Written: -tapenonstop

By default, the archiver writes a tape mark, an end of life (EOF) label, and two more

tape marks between archive files. When the next archive file is started, the driver

backs up to the position after the first tape mark, causing a loss of performance. The

–tapenonstop parameter directs the archiver to write only the initial tape mark. In

addition, if the -tapenonstop parameter is specified, the archiver enters the

archive information at the end of the copy operation.

For more information on the –tapenonstop parameter, see the archiver.cmd(4)

man page.

Reserving Volumes: -reserve

By default, the archiver writes archive set copies to any volume specified by a

regular expression as described in the volume associations section of the

archiver.cmd file. However, you might sometimes want archive set volumes to

contain files from only one archive set. You can reserve volumes to satisfy this data

storage requirement.

The -reserve parameter reserves volumes for an archive set. When the –reserve

parameter is set and a volume has been assigned to an archive set copy, the volume

identifier is not assigned to any other archive set copy, even if a regular expression

matches it.

Note – A site that uses reserved volumes is likely to incur more cartridge loads and

unloads.

When a volume is selected for use by an archive set, it is assigned a reserved name,

which is a unique identifier that ties the archive set to the volume.

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US Robotics 7931 Guide de l'utilisateur Page 105