You can use the following unit specifiers to indicate the size of the device: ‘k’ or ‘K’ indicate kilobytes, ‘m’ or ‘M’ indicate megabytes and ‘g’ or ‘G’ indicate gigabytes. Although it is optional, Sybase recommends that you always include the unit specifier in both the disk init and create database commands to avoid confusion in the actual number of pages allocated. You must enclose the unit specifier in single or double quotes.
The following apply to the syntax for disk init:
You can specify the size as a float, but it is rounded down to the nearest whole value. For example, if you specify a size of 3.75G, it is rounded down to 3G.
If you do not specify a size:
disk init and disk reinit use the basic disk page size of 2K.
The size argument for create database and alter database is in terms of megabytes of disk piece. This value is converted to the number of logical page size that with which the master device was built.
Minimum size of a database. You cannot alter the size of a database device after running disk init.
If you are planning to use the new device for the creation of a new database, the minimum size depends on the logical page size used by the server, described in Table 16-1:
Logical page size |
Minimum database size |
|---|---|
2K |
2 Megabytes |
4K |
4 Megabytes |
8K |
8 Megabytes |
16K |
16 Megabytes |
If you are initializing a database device for a transaction log or for storing small tables or indexes on a segment, the size can be as small as 512 blocks (1MB).
If you are initializing a raw device, determine the size of the device from your operating system, as described in the the installation documentation for your platform. Use the total size available, up to the maximum for your platform. After you have initialized the disk for use by Adaptive Server, you cannot use any space on the disk for any other purpose.
disk init uses size to compute the value for the high virtual page number in sysdevices.high.
WARNING! If the physical device does not contain the number of blocks specified by the size parameter, the disk init command fails. If you use the optional vstart parameter, the physical device must contain the sum of the blocks specified by both the vstart and size parameters, or the command fails.
