Nathan,

> Exactly! Even with proper direct write configuration of the USB drive
> , I still occasionally experience "Delayed Write Failed" errors. So,
> my question is this: What is likely to happen to a FB DB when a write
> fails? Will the DB be corrupted? Will it be recoverable? Or will
> everything be fine, just data from the failed transaction missing?

The best answer I can give is:

It depends.

Although the Firebird engine is written at its core to follow a "careful
write" strategy, there are devices which have 'optimizations' which can
render useless.

Consider a disk controller which allows the user to enable its
"write-back" (flush writes to disk in background) feature without a
battery-backup cache (this features allows the controller to 'optimize'
the order of disk writes based on the hardware/disk configuration).

In this case, a server crash would most likely result in a trashed
database, the controller 'lied' to the OS and the 'careful writes' have
been bypassed.

A similar 'optimization' could be implemented by USB drive vendors,
without you or your user knowing.

Personally, I would not support USB devices as the primary database
media.


Sean