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CHAPTER 3 Working with Database Objects
115
When data is stored on raw partitions, you can have one dbspace per drive.
When data is stored in a file system, you can take advantage of striping in the
storage system. If you use operating system or hardware striping on a multiuser
system, your stripe size should be a minimum of 1MB, or the highest size
possible. In any case, your stripe size should be several times your IQ page
size.
For more information on disk striping and use of multiple dbspaces, see
“Balancing I/O”.
Before adding any more dbspaces you may want to estimate your space
requirements. See “Estimating space and dbspaces required” for details of how
to estimate space. For the most efficient resource use, make your dbspaces
small enough to fit on your backup media, and large enough to fill up the disk.
Example
The following command creates a new dbspace called library in the file
library.iq in the same directory as the
IQ_SYSTEM_MAIN dbspace:
CREATE DBSPACE library
AS ’library.iq’
Creating a dbspace in
Sybase Central
❖ To create a dbspace in Sybase Central:
1 Connect to the database.
2 Click the Dbspaces folder for that database.
3 Double-click Add Dbspace in the right panel.
4 Enter the dbspace name.
5 Click the type of data to be stored in this Dbspace: IQ or IQ temporary.
6 Enter the filename, and optionally the size of the dbspace.
7 Click OK to create the dbspace.
Issuing checkpoints
for cleaner recovery
After you add or drop a dbspace, it's a good idea to issue a CHECKPOINT. In
the event system recovery is needed, it begins after the most recent checkpoint.