Scott: The NetWare statistics we viewed told us that it was a NetWare Core Protocol (NCP) request issue, but we saw few other specifics.

Bill: Once again, we carefully changed one server parameter at a time and monitored error statistics on the analyzer and the server. In the end, we were able to identify a parameter that, when turned on, caused the problem to stop immediately.

Scott: By carefully turning the parameter on and off, we were able to manipulate the problem to be present or nonexistent on demand.

Bill: Once we had a repeatable situation, we were able to view some related disk system statistics that lead us to the cause of the problem and enabled us to determine why it was intermittent for so many months.

Scott: OK, enough suspense already! What was the server parameter?

Bill: "Immediate purge of deleted files" was turned off. Novell NetWare installs this feature automatically, and it can protect accidental file erasure. If a user deletes a file, the administrator can recover it using the Salvage command. Although this feature has undeniable value, there should be a warning about its potential performance hit in some application environments.

Scott: So, when the NetWare Salvage command is invoked in an environment with a high rate of file creation and deletion, it causes the system to slow down?

Bill: Exactly. It's doubtful that Novell reali zes that excessive "server busy" packets are generated specifically in heavy file create, delete and rename environments, as with fax and imaging servers.

Scott: So, with our customer's Image Server set to its default condition of not purging from the disk, files remain on the disk until they are manually purged by the administrator or deleted by the server only when a certain percentage of the disk space remains for new files.

Bill: Right. When the server starts to run out of room on the hard drive, it starts purging the drive by looking for the oldest files.

Scott: When the server is already being taxed by the processing load, including requests for new files to be created, the system slows to a crawl and nothing is accomplished--new work or purging of old files.

Bill: Overriding the default configuration of retaining deleted files allowed the file server space to be recovered immediately, resulting in a major reduction in the respon se time of the imaging application.

Scott: As for file recovery, the client rarely used this feature because most of the imaging files were temporary conversions. Good tape backup procedures were in place for long-term storage. n

Bill and Scott can be reached at otw@pmg.com. Portions of trace files from selected columns are available via Pine Mountain Group's Home Page (www.pmg.com).