Detecting and Reporting File Write Failure

AS/U currently performs physical file writes after sending the SMB response back to the client. While this produces the best performance, it prevents the server from correctly responding to out of disk space conditions. This means a client can write to a file and never know that the write failed because the HP-UX file system is out of space. AS/U allows detection and reporting of write failures.

The registry value WriteBehind controls whether the server issues the write system call before or after responding to the client. The default value for this parameter is 1 which matches the current AS/U behavior. If the value is 1, the server sends an SMB response back to the client and then performs the physical file writes. If the value is 0, the server issues the write system call and returns the appropriate message to the client based on the results of the write.

Choosing 1 provides the best performance while choosing 0 will ensure that the client receives write errors such as disk full.