On Tue, 27 Jul 2004, Gary Kypers wrote: > I have a "diskless" client that boots from LTSP. The > client runs a program locally that talks through the > serial port to a measuring device. Normally the LAN > connection will be up but the server can go down on > occasion or the network may go down on occasion. In > practice an interruption of either the server or the > LAN stop the program, which writes to a local ramdisk. > This is undesireable because the measurements need to > be continuous. > > Here's what I see: > > The root (/) the client is the /opt/ltsp/i386/ of the > server which is accessed via the network.. > > Inside the root is the /mnt subdirectory. > > I created a ramdisk (/dev/ram0), did the mkfs y > mounted it as /mnt/DD. Up to this point all is well. I > can read and write to and from /mnt/DD from programs > running on the client so long as the client can see > the LTSP server. > > If I disconnect the LAN cable, the program that writes > to /mnt/DD stops and I get the following message: > > nfs server 192.168.0.254 not responding. Still > trying > > This occurs even though the ultimate target is a local > ramdisk. The local ramdisk of the client is mounted on > a subdirectory of the server. When the server is > disconnected there is no way to reach the local > ramdisk. (Does this mean that each read/write to the > local ramdisk is going through the network? Or is the > "pointer" the program uses a local one?).
I have a hunch that the problem is due to the / filesystem being on nfs. To write to /mnt/DD, it must walk the directory tree, starting at /, then mnt, then DD. It's the / and mnt that is depending on the network. The actual writing of the data is occuring completely locally, without going over the net. Does the program open->write->close the file each time ? I wonder if opening the file on bootup, and closing it later would help the situation. At least then, I don't think the tree would have to be traversed. This is an interesting problem, and i'll see what else I can think of. Jim McQuillan [EMAIL PROTECTED] > > What I think I need is another local "root". That is > to say, a place to mount local devices that does not > depend on the LTSP server so that the LTSP server > could be disconnected but the local programs continue > working. > > I've looked at several explanations of the "mount" > command. In all cases it is used to mount a device > onto a directory that already exists. I see no > information on how to create a initial mount point > that is local to the client.. > > To see if the problem was program execution I created > a "counter" program. It runs even when the LAN cable > is disconnected. So it appears that the problem is > when the programs attempt to access the local ramdisk > via the root. > > Thanks for any help! > Grey > > > > _______________________________ > Do you Yahoo!? > Express yourself with Y! Messenger! Free. Download now. > http://messenger.yahoo.com > > > ------------------------------------------------------- > This SF.Net email is sponsored by BEA Weblogic Workshop > FREE Java Enterprise J2EE developer tools! > Get your free copy of BEA WebLogic Workshop 8.1 today. > http://ads.osdn.com/?ad_id=4721&alloc_id=10040&op=click > _____________________________________________________________________ > Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto: > https://lists.sourceforge.net/lists/listinfo/ltsp-discuss > For additional LTSP help, try #ltsp channel on irc.freenode.net > ------------------------------------------------------- This SF.Net email is sponsored by BEA Weblogic Workshop FREE Java Enterprise J2EE developer tools! Get your free copy of BEA WebLogic Workshop 8.1 today. http://ads.osdn.com/?ad_id=4721&alloc_id=10040&op=click _____________________________________________________________________ Ltsp-discuss mailing list. To un-subscribe, or change prefs, goto: https://lists.sourceforge.net/lists/listinfo/ltsp-discuss For additional LTSP help, try #ltsp channel on irc.freenode.net
