On 02/20/2015 09:32 AM, Peter Rajnoha wrote: > On 02/19/2015 11:19 PM, Joel Friedly wrote: >> I'm trying to some disk failure testing, and we're using LVM on top of >> raw disks. After replacing the disk, the LV on the disk is unreadable >> until I run vgmknodes --refresh. That command hangs forever, but I can >> kill -9 it. After running the command, everything works again and I can >> read the LV. >> >> I've seen this twice, so I ran strace the second time and you can find >> the output here: https://gist.github.com/jfriedly/50fe9134c4bc616f9f90 >> and Ctrl-F for "425989" >> >> On line 4250, LVM sets the semaphore's value to 1, then it immediately >> checks the semaphore's value and confirms that it's 1. >> >> On line 4253, LVM increments the semaphore's value to 2, then it >> immediately checks the semaphore's value and confirms that it's 2. >> >> On line 4295, LVM gets the semaphore's value and sees that it's 2, then >> it immediately decrements the value to 1 and then waits indefinitely for >> the value to hit 0. >> >> >> Is LVM expecting some other process to decrement the semaphore? > > Yes, it's expecting notification from udev rule - the 95-dm-notify.rules > (usually found in /lib/udev/rules.d directory) - that one contains > "dmsetup udevcomplete" call which decrements the semaphore. The --refresh > causes CHANGE udev events to be generated for the LV and LVM waits for > any udev processing to be finished before it continues further. > > What Linux distribution is this? > (Sorry, you've added that info already, I've noticed - it's Ubuntu.) -- Peter _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
