zumbachl@softeng1.UUCP (Lyle Zumbach) (10/12/89)
Both Sun's PC/NFS and FTP's Interdrive don't seem to handle network connection loss very well. It seems like there is a high chance of losing data (and not knowing about it) if you lose your network connection. Is this true? Shouldn't the user be presented with the Abort, Retry, Ignore message (DOS critical error handler?) ? Does the fact that NFS is a stateless protocol cause the problem?
geoff@hinode.East.Sun.COM (Geoff Arnold @ Sun BOS - R.H. coast near the top) (10/13/89)
In article <6@softeng1.UUCP> zumbachl@softeng1.UUCP (Lyle Zumbach) writes: > >Both Sun's PC/NFS and FTP's Interdrive don't seem to handle >network connection loss very well. It seems like there is >a high chance of losing data (and not knowing about it) if you >lose your network connection. Is this true? Shouldn't the user >be presented with the Abort, Retry, Ignore message (DOS critical >error handler?) ? Does the fact that NFS is a stateless protocol >cause the problem? PC-NFS will indeed give you an "Abort, Retry, Ignore" on timeouts. The number of retries is configurable (via the "/r" switch); if you set "/r0" we'll retry forever (or until a Ctrl-Break). The default number is 4. Note that we use an exponential backoff up to a 30 second retry interval; the initial value and the backoff rate depend on the network connection. As for losing data, the timeout condition is treated the same as a Drive Not Ready on a diskette. If you select "Retry", the system call is restarted by DOS, and if the network is now ok (e.g. the server has rebooted) you'll lose no data. I'll let James comment on InterDrive. Geoff Arnold, Internet: geoff@East.Sun.COM PCDS Group, Sun Microsystems Inc. --------------------------------------------------------------------------- "Who's next?" "Me, doctor?" "No, ME doctor, YOU patient." (Graham Chapman, RIP)
corwin@ftp.COM (Walter Stickle) (10/18/89)
In article <6@softeng1.UUCP> zumbachl@softeng1.UUCP (Lyle Zumbach) writes: >Both Sun's PC/NFS and FTP's Interdrive don't seem to handle >network connection loss very well. It seems like there is >a high chance of losing data (and not knowing about it) if you >lose your network connection. Is this true? Shouldn't the user >be presented with the Abort, Retry, Ignore message (DOS critical >error handler?) ? Does the fact that NFS is a stateless protocol >cause the problem? Well, Since Geoff answered for PC/NFS, I'll just answer for InterDrive. While waiting for a transaction response, InterDrive uses an adaptive retransmit algorhythim to retry for a configurable amount of time. In the case of a timout, the current version does return an error. The assumption was that most routines would check for error returns, making the critical error handling a moderatly low priority. It has become clear that this is a bad assumption, and that simply returning an error is the *wrong* thing to do. So... DOS critical error handling has been added to the next release (currently under development), to allow the user the "Abort, Retry, Ignore" options. Like the current version, the time before the timout will be configurable, but no error will be returned (and no data lost) unless the user so chooses. -wls ----------------------------------------------------------------------------- Walter L. Stickle corwin@vax.ftp.com ..!ftp!corwin Hacking Networking for FTP Software, Wakefield MA (617)-246-0900 ...and playing Guitar until my fingers fall off... ext. 277 ------------------------------------------------------------------------------- Walter L. Stickle corwin@vax.ftp.com ..!ftp!corwin Hacking Networking for FTP Software, Wakefield MA (617)-246-0900 ...and playing Guitar until my fingers fall off... ext. 277