Caching storage data

The server-side caching of storage data is supported on the cache devices.

The cache devices can be one of the following types of devices:

  • Server-attached flash devices, such as built-in solid-state drive (SSD) in the server.
  • Flash devices that are directly attached to the server by using Serial Attached SCSI (SAS) controllers.
  • Flash resources in the storage area network (SAN).

The AIX operating system must identify the device as a flash device for it to be used as a cache device. The AIX operating system determines if a device is a flash device by using the MEDIUM ROTATION RATE field in the SCSI Block Device Characteristics Vital Product Data (VPD) page. If a device does not support that page or puts a value other than 0001h Non-rotating medium in the MEDIUM ROTATION RATE field, then the device cannot be used as a cache device.