The Metadata Controller System

The CPU power and memory capacity of the MDC System are important performance factors, as well as the number of file systems hosted per system. In order to ensure fast response time it is necessary to use dedicated systems, limit the number of file systems hosted per system (maximum 8), and have an adequate CPU and memory. Refer to the StorNext User’s Guide for limits on the number of files per file system and per database instance.

Some metadata operations such as file creation can be CPU intensive, and benefit from increased CPU power.

Other operations can benefit greatly from increased memory, such as directory traversal. SNFS provides two config file settings that can be used to realize performance gains from increased memory:

  • BufferCacheSize
  • InodeCacheSize

However, it is critical that the MDC system have enough physical memory available to ensure that the FSM process doesn’t get swapped out. Otherwise, severe performance degradation and system instability can result.

The operating system on the metadata controller must always be run in U.S. English. On Windows systems, this is done by setting the system locale to U.S. English.

Caution: As the File System Manager (FSM) supports over 1000 clients (with more than 1000 file requests per client), the resource limits of your MDC may be exhausted with additional load from other processes. Exceeding the file descriptor limit will cause errors to your system. Quantum recommends you not run additional applications on the MDC.