Sybase DC35823-01-1500-04 Creating files for database devices, Managing database devices, 110

Managing database devices

•The minimum device size for a 16K page server is 4MB

•The maximum number of database devices is 2,147,483,647. However, Adaptive Server must retain a description of each device in memory, so in practice this number is limited by your system’s memory. Your operating system also limits how many devices one program can open simultaneously.

•A database can contain up to 2,147,483,648 logical pages, so its maximum size depends on its logical page size:

•The maximum database size on a 2K page server is 4TB.

•The maximum database size on a 4K page server is 8TB.

•The maximum database size on an 8K page server is 16TB.

•The maximum database size on a 16K page server is 32TB.

•The minimum database size is the size of the installation’s model database.

•Each database is stored on one or more database devices, in one or more disk pieces. The maximum number of disk pieces in one database is 8, 388,608. However, Adaptive Server must retain a description of all active databases, so in practice this number is also limited by your operating system memory.

Note By default, srvbuild creates the devices in $SYBASE/data directory.

Creating files for database devices

You can create new database devices using the disk init command. You can specify a raw partition or operating system file. When using a raw partition, you must specify the full path to the partition. When using an operating system file, you may use the full path or a relative path. Path names are relative to your server’s current working directory.

Sybase recommends that you specify the full path to all database devices. Do not use environment variables when specifying path names with disk init.

Here is an example of creating a database device using disk init:

disk init name = "user_device1", physname = "/work/data/device1.dat", size = 2048

110 Adaptive Server Enterprise