1.11 mvEnterprise Disk Flushing Program
This program is available on the AIX systems, and would normally replace the native system syncd or fsflush daemons (background processes). The program is mvEnterprise machine specific and performs as follows:
The mvEnterprise database is divided into two segments; the space above the system file base (SYSBASE) and the space below it, enabling aggressive flushing of the data frames (those located above SYSBASE). Flushing of the workspace frames (below SYSBASE) is unnecessary.
The data space is divided into approximately equal sections (slices). Each section on a single drive is mmaped and flushed to disk. The disk flusher then sleeps a prescribed amount of time and then continues to the next section on the next disk drive.
This process allows flushing of the entire file system data space in approximately in n x m (where n equals the number of sections and m equals the sleep time in seconds). The defaults for the program are 60 sections and a
NOTE: The workspace below SYSBASE is not normally synchronized (synced) since it contains no useful data in the event of a system crash.
After completing a number of data space flush cycles (loops), the program attempts to sync first the entire mvEnterprise virtual machine and finally the entire system. The last step is necessary because the user may have terminated the standard AIX synced process.
The act of syncing the entire machine may create the same performance problems the user is attempting to avoid. To minimize this possibility, most of the system should already be flushed before issuing the sync request. The program performs the following tasks:
Changes the sleep setting on the last pass through the data frames to a much smaller value.
Syncs sections of the work space using this smaller sleep time.
Executes fsync (an AIX system call) on the mvEnterprise file systems with the smaller sleep time.
Issues the system wide sync.
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