See what components Extended Adaptive Cache requires and learn more about what to expect.
Before you begin using Extended Adaptive Cache, you should do some initial planning to take into account any restrictions or considerations that may pertain to your computing environment.
To use Extended Adaptive Cache, your system must have the following:
Extended Adaptive Cache is automatically enabled on supported I/O adapters. There is no controlled on or off switch. Once the I/O adapter has been inserted into the subsystem, Extended Adaptive Cache is activated. It takes approximately an hour for Extended Adaptive Cache to monitor the data flow and populate the read cache memory. After an hour of running Extended Adaptive Cache, your system should show improved performance (depending on your current workload) and increased I/O throughput.
There are no restrictions for using Extended Adaptive Cache with regard to device parity protection and mirrored protection for other disks under the I/O adapter. Finally, Extended Adaptive Cache is designed specifically to complement iSeries Expert Cache, and may be used with or without it.
Using the Extended Adaptive Cache allows you to attain a significant decrease in I/O response time and increase in system I/O throughput in most environments. As is the general case with caches, the system configuration and workload influence the effectiveness of Extended Adaptive Cache. Extended Adaptive Cache performs at the storage subsystem level. It caches data for the set of disks that are within that specific subsystem. Therefore, it is logical to add Extended Adaptive Cache to the most active and performance-critical storage subsystems within the system. Extended Adaptive Cache is not considered a pre-fetch type cache and therefore will not interfere with the read-ahead capabilities in the disk.
The larger the area of disk storage that is actively receiving I/O requests, the more selective Extended Adaptive Cache is about deciding when to bring new data into cache. This adaptive ability allows Extended Adaptive Cache to be effective on many workload types and sizes.