realfstab File

Partition databases that occupy multiple partitions (UNIX only) or files on different file systems (see Types of Database for details) must be defined in the realfstab host file:

• On UNIX, edit the file /etc/realfstab - you must be superuser to edit this file.

• On Windows, edit the file realfstab in the realman Directory - you can find the location of the realman directory by using the Defaults option in the netadmin host utility.

The database definitions are used by the mkdbase host command to create the databases. Refer to Creating and Removing a Database for more information.

Syntax

Each entry in realfstab consists of a directory name or absolute path at the start of a line, followed by a list of storage elements (absolute paths to partitions or files). Items within an entry are separated by white space (spaces or tabs), and continuation lines must start with white space.

directory element element element ...
element element element ...

If you specify just a directory name, when the database is created with mkdbase, the base directory will be created in the current directory.

Stripe Zones

When entered as above, the storage elements are grouped into a single stripe zone. If your disks have multiple partitions (UNIX only), you can use parentheses group your storage elements into stripe zones, each containing one element from each disk. For example.

directory (disk1element1 disk2element1 disk3element1)
(disk1element2 disk2element2 disk3element2)
(disk1element3 disk2element3 disk3element3)

For Reality striping to work correctly, all the storage elements in a stripe zone must be the same size.

Unstriped Storage Elements

There are two ways to to increase the size of your partition database:

• You can change your striping scheme to add new elements and then rebuild your database with mkdbase -r.

• You can add more storage elements outside the striping scheme and then run mkdbase with the -a option to incorporate them into the database. Add the new elements to the end of the list, preceded by a plus sign (+). For example:

directory element1 element2 element3
element4 element5 element6
+ newElement1 newElement2

Comments

Any text following a hash (#) is ignored until the start of the next line. Any lines that consist entirely of white space are also ignored.

Multiple Partition Database

For a database on multiple partitions (UNIX only), each storage element must be the absolute path to a disk partition device. For example:

/accounts/dbase	(/dev/dsk/d1s1 /dev/dsk/d2s1 /dev/dsk/d3s1)
		(/dev/dsk/d1s2 /dev/dsk/d2s2 /dev/dsk/d3s2)
		+ /dev/dsk/d0s3

Multiple File Database

For a database that uses host files on different file systems, each storage element must be the absolute path to a file, followed by a comma and a file size. For example, to specify a database in the directory pdb that consists of two files, each of 20,000 1 kilobyte blocks, enter:

pdb /fs1/file1,20000 /fs2/file2,20000

If you use a dash (hyphen) as the file size this specifies that the file should fill the file system; for example:

pdb /fs1/file1,- /fs2/file2,-