On Tue, Aug 03, 2010 at 08:04:29PM +0200, Peter Simons wrote: > Hi guys, > > first of all, thanks a lot for the effort you're putting into nbd. The > package has handled my off-site backups gracefully for 2+ years, so I am > one happy user! > > Now, it looks to me like my kernel performs too much write-buffering. > When a large file is copied to an nbd-mounted partition, the initial 2 > MB or so are transferred at incredible speed; apparently, because the > kernel just buffers the data. At one point, the kernel actually tries to > transfer the data to the remote host, but that takes several minutes. > During that time, the nbd-device is almost unusable for other processes > because it accepts no more writes at all (and reads have a hard time > getting through the network connection). > > Has anyone else observed that phenomenon? Is there maybe a way to > improve the situation?
You can try to change the I/O scheduler. The default for most devices is "cfq", but that isn't very useful for nbd. The 'deadline' one could yield better results. -- The biometric identification system at the gates of the CIA headquarters works because there's a guard with a large gun making sure no one is trying to fool the system. http://www.schneier.com/blog/archives/2009/01/biometrics.html ------------------------------------------------------------------------------ The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://p.sf.net/sfu/dev2dev-palm _______________________________________________ Nbd-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nbd-general
