COMPATIBILITY PREV610A_FLUSH suppresses the flushing of updated file system cache pages to disk when a non-transaction WRITETHRU file is updated. See COMPATIBILITY FORCE_WRITETHRU.
This option is off by default. Be sure to check your FairCom Server configuration file, as it might be enabled there.
The performance impact of WRITETHRU depends on whether COMPATIBILITY PREV610A_FLUSH is enabled:
When COMPATIBILITY PREV610A_FLUSH is NOT enabled, each update to a non-transaction WRITETHRU file is flushed to disk. Both c-tree and operating system (OS) caches are flushed. This mode, while extremely safe, can significantly slow down performance of updates to non-transaction WRITETHRU files.
When COMPATIBILITY PREV610A_FLUSH is enabled, each update to a non-transaction WRITETHRU file is flushed to the OS file system cache, but the updated pages in the OS file system cache are not flushed at the time of the update. This mode performs much faster than when each update flushes the file system cache updates to disk, but note that the contents of updated file system cache pages can be lost if the system loses power before the operating system has written the updated file system cache pages to disk. Installing a power supply on the system can reduce the likelihood of losing data in the event that a system power loss occurs by permitting time for the operating system to write updated file system cache pages to disk.