PRIMECLUSTER Global File Services Configuration and Administration Guide 4.2 (Solaris(TM) Operating Environment)

15.2.1 Effects of file system operation and system load

To maintain strict file system consistency, the GFS Shared File System processing sometimes significantly slows down during the following operations:

• When frequently creating or deleting a file or directory in the same directory from multiple nodes, and repeatedly monitoring directory updating with readdir(3C) or stat(2).
• When frequently updating the same block in the same file from two or more nodes.
• When frequently referencing from other nodes a file that is frequently updated from one or more nodes.
• When an ls(1) command with the -l option and a command requiring attributes of files under the directory such as cp(1), du(1M), and tar(1) are both issued to a directory contains at least 10,000 files.

In the above cases, file system throughput may improve by changing the monitoring or access frequency or by dividing a target file.

CPU load or I/O load may be concentrated on the node where the MDS that manages the file system meta-data operates. A heavy load here indicates that operations accompanying updating of the file system meta-data, such as file creation, deletion, or extension are frequently being done. In such cases, file system throughput may improve by optimizing the layout of the meta-data area and update log area. An alternative is to increase CPU throughput of the node where the MDS operates.