Summary information |
|
|---|---|
Default value |
256 |
Range of values |
0–2147483647 |
Status |
Dynamic |
Display level |
Comprehensive |
Required role |
System administrator |
Configuration group |
Disk I/O, Memory Use |
disk i/o structures specifies the initial number of disk I/O control blocks Adaptive Server allocates at start-up.
User processes require a disk I/O control block before Adaptive Server can initiate an I/O request for the process. The memory for disk I/O control blocks is preallocated when Adaptive Server starts. To minimize the chance of running out of disk I/O structures, you should configure disk i/o structures to as high a value as your operating system allows. See your operating system documentation for information on concurrent disk I/Os.
Use sp_sysmon to determine whether to allocate more disk I/O structures. See the Performance and Tuning Series: Monitoring Adaptive Server with sp_sysmon. You can set the max async i/os per server configuration parameter to the same value as disk i/o structures. See “max async i/os per server”.
