Adjusting the Operating System Shared Memory Parameters

Adjust shared memory segments if Adaptive Server cannot obtain large memory as a single segment, or if Backup Server stripes fail due to insufficient segments.

Depending on the number and types of devices used for backup (dump) and recovery (load), you may need to adjust the shared memory segment parameter in the operating system configuration file to accommodate concurrent Backup Server processes. There are six default shared memory segments available for process attachments.

If any reconfiguration through sp_configure requires additional memory, Adaptive Server allocates shared memory segments after start-up. To account for these additional segments, allocate the maximum memory available to Adaptive Server by using the allocate max shared memory configuration parameter. See the System Administration Guide.

Adaptive Server version 15.5 and later require an additional 32MB of shared memory than earlier versions. The default size of the max memory configuration parameter is 280MB. Increase this value to accommodate any additional memory requirement.
To query the amount of shared memory, enter:
```
# kctune shmmax
```
To increase the amount of shared memory, for example, to 335MB, enter:
```
# kctune shmmax+=33554432
```
To adjust the shared memory value of the operating system, use the System Administration Manager (SAM). After you install Adaptive Server, change any configuration parameter, procedure cache, or data cache size. This may require you to increase the value of the max memory configuration parameter.