Commands for Managing Disk Resources

SAP ASE offers many commands and strategies for managing disk resources.

Command

Task

See

disk init
  name = "dev_name"
  physname = "phys_name"...

Makes a physical device available to a particular SAP ASE. Assigns a database device name (dev_name) that is used to identify the device in other SAP ASE commands.

System Administration Guide: Volume 1 > Initializing Database Devices

sp_deviceattr logicalname, 
  optname, optvalue

Changes the dsync setting of an existing database device file.

System Administration Guide: Volume 1 > Initializing Database Devices

sp_diskdefault "dev_name"...

Adds dev_name to the general pool of default database space.

System Administration Guide: Volume 1 > Initializing Database Devices

disk resize
  name = “device_name”,
  size = additional_space

Dynamically increases the size of database devices.

System Administration Guide: Volume 1 > Initializing Database Devices

disk mirror
  name = "dev_name"
  mirror = "phys_name"...

Mirrors a database device on a specific physical device.

System Administration Guide: Volume 2 > Mirroring Database Devices

The table below lists the commands used in object placement. For information about how object placement affects performance, see Performance and Tuning Series: Physical Database Tuning > Controlling Physical Data Placement.

Commands for placing objects on disk resources

Command

Task

See

create database...on dev_name

or

alter database...on dev_name

Makes database devices available to a particular SAP ASE database. The log on clause to create database places the database’s logs on a particular database device.

System Administration Guide: Volume 2 > Creating and Managing User Databases

create database...

or

alter database...

When used without the on dev_name clause, these commands allocate space on the default database devices.

System Administration Guide: Volume 2 > Creating and Managing User Databases

sp_addsegment seg_name, 
  dbname, devname

and

sp_extendsegment seg_name,
  dbname, devname

Creates a segment—a named collection of space—from the devices available to a particular database.

System Administration Guide: Volume 2 > Creating and Using Segments

create table...on seg_name

or

create index...on seg_name

Creates database objects, placing them on a specific segment of the database’s assigned disk space.

System Administration Guide: Volume 2 > Creating and Using Segments

create table...

or

create index...

When used without on seg_name, tables and indexes occupy the general pool of space allocated to the database (the default devices).

System Administration Guide: Volume 2 > Creating and Using Segments in System