Summary information |
|
|---|---|
Default value |
6 |
Valid values |
1–256 |
Status |
Dynamic |
Display level |
Comprehensive |
Required role |
System Administrator |
The number of large i/o buffers parameter sets the number of allocation unit-sized buffers reserved for performing large I/O for certain Adaptive Server utilities. These large I/O buffers are used primarily by the load database command. load database uses one buffer to load the database, regardless of the number of stripes it specifies. load database then uses up to 32 buffers to clear the pages for the database it is loading. These buffers are not used by load transaction. If you need to perform more than six load database commands concurrently, configure one large I/O buffer for each load database command.
create database and alter database use these buffers for large I/O while clearing database pages. Each instance of create database or load database can use up to 32 large I/O buffers.
These buffers are also used by disk mirroring and by some dbcc commands.
In Adaptive Server version 12.5.03 and above, the size
of the large I/O buffers is now one allocation (256 pp),
not one extent (8 pp). The server thus requires more memory allocation
for large buffers. For example, a disk buffer that required memory
for 8 pages in earlier versions now requires memory for 256 pages.
