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76 Sun StorageTek SAM Archive Configuration and Administration Guide • Version 4, Update 6, 04/07

When you use the –drives parameter, multiple drives are used only if data that is

more than the value of min-size is to be archived. The number of drives to be used in

parallel is the lesser of the following two values:

■ The size of the archive request divided by the value of min-size

■ The number of drives specified by the –drives parameter

You can use the –drivemin and -drives parameters if you want to divide an

archive request among drives but don’t want to have all the drives bust with small

archive requests. This might apply to operations that use very large files.

To set these parameters, you need to consider file creation rates, the number of

drives, the time it takes to load and unload drives, and drive transfer rates.

For example, suppose that you are splitting an archive set named bigfiles over

five drives. Depending on its size, this archive set could be split as shown in

TABLE 3-15.

CODE EXAMPLE 3-23 shows the lines to use in the archiver.cmd file to split the

archive request over multiple drives.

In addition, you might specify the following line in the archiver.cmd file:

When the total size of the files in archive set huge_files.2 is equal to or greater

than two times drivemin for the media, two drives are used to archive the files.

TABLE 3-15 Archive Set Example Split

Archive Set Siz e Number of Drives

< 20 gigabytes 1

> 20 gigabytes to < 30 gigabytes 2

> 30 gigabytes to < 40 gigabytes 3

> 40 gigabytes to < 50 gigabytes 4

> 50 gigabytes 5

CODE EXAMPLE 3-23 Directives Used to Split an Archive Request Over Multiple Drives

params

bigfiles.1 –drives 5 –drivemin 10G

endparams

huge_files.2 -drives 2

1 2 ... 95 96 97 98 99 100 101 102 103 104 105 ... 287 288

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