Pinned memory

GPFS™ uses pinned memory (also called pagepool memory) for storing file data and metadata in support of I/O operations.

With some access patterns, increasing the amount of pagepool memory can increase I/O performance. Increased pagepool memory can be useful in the following cases:
  • There are frequent writes that can be overlapped with application execution.
  • There is frequent reuse of file data that can fit in the pagepool.
  • The I/O pattern contains various sequential reads large enough that the prefetching data improves performance.

Pinned memory regions cannot be swapped out to disk, which means that GPFS will always consume at least the value of pagepool in system memory. So consider the memory requirements of GPFS and other applications running on the node when determining a value for pagepool.

Parent topic: GPFS and memory