Adding hard disks

Dividing a disk partition into divisions using divvy

Use divvy(ADM) to divide a UNIX system partition into a maximum of seven divisions (0 to 6). You can use these divisions as filesystems or swap areas. Division 6 (recover) is reserved for use by fsck(ADM) on the root disk only. Division 7 is reserved and refers to the entire partition.

divvy displays a table of the current divisions within a UNIX partition. To change this table, use the following one-letter commands to:

name a division. This creates a corresponding block device file for accessing the division, for example, /dev/x for a division named x. Do not name a division usr.

create a division. Used to bring a division into use.

select the filesystem type of a division. Divisions can be one of the supported filesystem types such as HTFS or DTFS, and NON FS for a swap or recover area.

prevent a filesystem from being created on a division.

define the start logical block for a division. divvy displays the total number of filesystem logical (1KB) blocks available. Note that a filesystem logical block is not the same as a physical disk block or a SCSI logical block (which are typically 512 bytes in size). Do not allow any of divisions 0 to 6 to overlap; a division cannot start on or before the end block of the previous division.

define the end logical block for a division.

restore the division table to the state it was in when you entered divvy.
Changes are not final until you quit divvy and select install (i) from the closing menu. To leave divvy without saving your changes, select exit (e) from the closing menu.

Creating and resizing divisions

If you are partitioning your primary hard disk at install time, you can reallocate the space used by the default root division to create multiple filesystems. Do not change the other divisions (including swap, recover, and boot) unless you are an experienced administrator. For the primary hard disk, you would first shrink the root division using the e command to define the new ending block. You can then create and name a new division that starts after the ending block of the resized root division and ends at the old ending block for the root division.

NOTE: You can have a maximum of 7 filesystems. The maximum filesystem size that you can create using divvy is 1 terabyte for DTFS and HTFS, and 2GB for other filesystems. Depending on file sizes, you may experience performance problems with filesystems larger than 100GB to 350GB.

If you have an unusually large number of files on a filesystem bigger than 18GB, we recommend using DTFS filesystems with compression disabled.

Example: secondary hard disk

The following example of the information displayed by divvy shows a 1GB SCSI disk configured as the second disk in a system, with one 635MB HTFS and one 354MB DTFS filesystem:

| Name     | Type        | New FS | # | First Block | Last Block |
| u        | HTFS        |  no    | 0 |            0|      649999|
| x        | DTFS        |  no    | 1 |       650000|     1012734|
|          | NOT USED    |  no    | 2 |            -|           -|
|          | NOT USED    |  no    | 3 |            -|           -|
|          | NOT USED    |  no    | 4 |            -|           -|
|          | NOT USED    |  no    | 5 |            -|           -|
|          | NOT USED    |  no    | 6 |            -|           -|
| hd1a     | WHOLE DISK  |  no    | 7 |            0|     1013743|

1012735 1K blocks for divisions, 4008 1K blocks reserved for the system

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SCO OpenServer Release 5.0.7 -- 11 February 2003