Hi Paul, Recently (that is, a few months ago), I did some initramfs hooks for Debian to allow the root filesystem to be on an NBD device. They work well, but Vagrant Cascadian (who maintains LTSP in Debian, which can optionally use NBD for quite a few things) pointed out one issue with this: when the system shuts down, there's no point in which userspace can safely issue an nbd disconnect message to the kernel anymore. As such, you rely on the TCP keepalive probes, which on a server serving for a high amount of clients (as is common in LTSP environments) might be problematic. Userspace can't do this, because that'd mean both poweroff and nbd-client would need to be the very last command issued in the shutdown sequence (running either makes doing the other impossible), so that's a non-option.
As such, I thought it'd make sense to have the NBD kernel module do so. Since the software-RAID subsystems seems to do a final sync right before a system poweroff occurs, I presume there's support in the kernel to hook into the poweroff sequence, and do some final cleanup operation. If NBD could hook into that and at that point just send an NBD_DISCONNECT message to the server, that would solve this issue. What do you think about that? -- 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 ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ Nbd-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nbd-general
