May 10May 10 While restarting the server, it always happens that it won't be a clean shutdown because there are unmounted disks.I found this thread, but there is no solution: https://forums.unraid.net/topic/91696-solved-cannot-unmount-mntcache-to-stop-array/I see the problem that /mnt/cache/appdata cannot be unmounted. It's my cache pool formatted with ZFS.May 10 03:31:13 UNRAID-Server emhttpd: Retry unmounting disk share(s)... May 10 03:31:13 UNRAID-Server emhttpd: shcmd (338594): exit status: 1 May 10 03:31:13 UNRAID-Server root: cannot unmount '/mnt/cache/appdata': pool or dataset is busy May 10 03:31:13 UNRAID-Server emhttpd: shcmd (338594): /usr/sbin/zpool export -f cache May 10 03:31:13 UNRAID-Server emhttpd: Unmounting disks... May 10 03:31:08 UNRAID-Server emhttpd: Retry unmounting disk share(s)... May 10 03:31:08 UNRAID-Server emhttpd: shcmd (338593): exit status: 1 May 10 03:31:08 UNRAID-Server root: cannot unmount '/mnt/cache/appdata': pool or dataset is busy May 10 03:31:08 UNRAID-Server emhttpd: shcmd (338593): /usr/sbin/zpool export -f cache May 10 03:31:08 UNRAID-Server emhttpd: Unmounting disks... May 10 03:31:04 UNRAID-Server root: Fix Common Problems Version 2025.08.07 System May 10 03:31:04 UNRAID-Server rc.local_shutdown: Generating diagnostics... May 10 03:31:04 UNRAID-Server rc.local_shutdown: fuser -mv /dev/md1p1 /dev/md2p1 May 10 03:31:04 UNRAID-Server rc.local_shutdown: Active pids left on /dev/md* May 10 03:31:04 UNRAID-Server rc.local_shutdown: fuser -mv /mnt/addons /mnt/cache /mnt/disks /mnt/remotes /mnt/rootshare May 10 03:31:04 UNRAID-Server rc.local_shutdown: Active pids left on /mnt/* May 10 03:31:04 UNRAID-Server rc.local_shutdown: losetup -a May 10 03:31:04 UNRAID-Server rc.local_shutdown: Status of all loop devices May 10 03:31:04 UNRAID-Server rc.local_shutdown: Forcing shutdown... May 10 03:31:03 UNRAID-Server emhttpd: Retry unmounting disk share(s)... May 10 03:31:03 UNRAID-Server emhttpd: shcmd (338592): exit status: 1 May 10 03:31:03 UNRAID-Server root: cannot unmount '/mnt/cache/appdata': pool or dataset is busy May 10 03:31:03 UNRAID-Server emhttpd: shcmd (338592): /usr/sbin/zpool export -f cache May 10 03:31:03 UNRAID-Server emhttpd: Unmounting disks... May 10 03:30:58 UNRAID-Server emhttpd: Retry unmounting disk share(s)... May 10 03:30:58 UNRAID-Server emhttpd: shcmd (338591): exit status: 1 May 10 03:30:58 UNRAID-Server root: cannot unmount '/mnt/cache/appdata': pool or dataset is busy May 10 03:30:58 UNRAID-Server emhttpd: shcmd (338591): /usr/sbin/zpool export -f cache May 10 03:30:58 UNRAID-Server emhttpd: Unmounting disks... May 10 03:30:53 UNRAID-Server emhttpd: Retry unmounting disk share(s)... May 10 03:30:53 UNRAID-Server emhttpd: shcmd (338590): exit status: 1 May 10 03:30:53 UNRAID-Server root: cannot unmount '/mnt/cache/appdata': pool or dataset is busy May 10 03:30:53 UNRAID-Server emhttpd: shcmd (338590): /usr/sbin/zpool export -f cache May 10 03:30:53 UNRAID-Server emhttpd: Unmounting disks... May 10 03:30:48 UNRAID-Server emhttpd: Retry unmounting disk share(s)... May 10 03:30:48 UNRAID-Server emhttpd: shcmd (338589): exit status: 1 May 10 03:30:48 UNRAID-Server root: cannot unmount '/mnt/cache/appdata': pool or dataset is busy May 10 03:30:48 UNRAID-Server emhttpd: shcmd (338589): /usr/sbin/zpool export -f cache May 10 03:30:48 UNRAID-Server emhttpd: Unmounting disks... May 10 03:30:43 UNRAID-Server emhttpd: Retry unmounting disk share(s)... May 10 03:30:43 UNRAID-Server emhttpd: shcmd (338588): exit status: 1 May 10 03:30:43 UNRAID-Server root: cannot unmount '/mnt/cache/appdata': pool or dataset is busy May 10 03:30:43 UNRAID-Server emhttpd: shcmd (338588): /usr/sbin/zpool export -f cache May 10 03:30:43 UNRAID-Server emhttpd: Unmounting disks... May 10 03:30:38 UNRAID-Server emhttpd: Retry unmounting disk share(s)... May 10 03:30:38 UNRAID-Server emhttpd: shcmd (338587): exit status: 1 May 10 03:30:38 UNRAID-Server root: cannot unmount '/mnt/cache/appdata': pool or dataset is busy May 10 03:30:38 UNRAID-Server emhttpd: shcmd (338587): /usr/sbin/zpool export -f cache May 10 03:30:38 UNRAID-Server emhttpd: Unmounting disks... May 10 03:30:33 UNRAID-Server emhttpd: Retry unmounting disk share(s)... May 10 03:30:33 UNRAID-Server emhttpd: shcmd (338586): exit status: 1 May 10 03:30:33 UNRAID-Server root: cannot unmount '/mnt/cache/appdata': pool or dataset is busy May 10 03:30:33 UNRAID-Server emhttpd: shcmd (338586): /usr/sbin/zpool export -f cacheBut what can I do about that? That has happened since the update to Unraid 7.2, as far as I remember. That is really not nice. UNRAID-ServerEnhancedLog.csv unraid-server-diagnostics-20260510-2223.zip
May 11May 11 Community Expert Disable Docker and VM service and reboot in safe mode, start the array and see if it stops, if yes, retest again after booting in normal mode to rule out a plugin issue, leave the services still disabled, if still OK enable one of the services and retest, then the other, note that if the issue happens with the docker service enabled only, you may need to try enabling one or a few containers at a time to find the culprit.
May 11May 11 Author @JorgeB let's say I did this and find one container causing it (which is hard anyway because I got more than 120), how should I fix this then?
May 11May 11 3 hours ago, sasbro97 said:@JorgeB let's say I did this and find one container causing it (which is hard anyway because I got more than 120)...Use a binary search to more quickly narrow down the troublesome container.
May 18May 18 Author In the process of migrating to an internal boot drive with no VM or Docker service running, I can see that the problem seems to be my ZFS dataset cache/appdata itself, or maybe the underlying cloud folder:
May 18May 18 Community Expert open terminal and type in lsof /mnt/cache/appdata and it will spit out a process, then type in kill -9 <process_ID> replace <process_ID> with the actual number. might have to repeat this depending on how many processes are accessing appdata.
May 18May 18 Author @MowMdown I know it should be like this, and I have had this very often now, but nothing that was stated in any thread here was correct. I did what you said, and 20 other things, and nothing worked. Because if you get rid of the particular dataset /mnt/cache/appdata, it was saying that the cache pool itself is busy or whatever. I hope this stops now after formatting. It appeared out of nowhere.Fun fact: I'm pretty sure it was this folder that was problematic. As I moved all the files in the process of migrating to an internal boot drive, everything worked fine. appdata was moved, and 150 containers simply work. Just the appdata/cloud folder was not correctly moved, and my config is gone. As I have not moved or replicated the ZFS snapshots, it's lost, but I can live with that. Edited May 19May 19 by sasbro97
May 19May 19 Community Expert 17 hours ago, sasbro97 said:@MowMdown I know it should be like this, and I have had this very often now, but nothing that was stated in any thread here was correct. I did what you said, and 20 other things, and nothing worked. Because if you get rid of the particular dataset /mnt/cache/appdata, it was saying that the cache pool itself is busy or whatever. I hope this stops now after formatting. It appeared out of nowhere.Fun fact: I'm pretty sure it was this folder that was problematic. As I moved all the files in the process of migrating to an internal boot drive, everything worked fine. appdata was moved, and 150 containers simply work. Just the appdata/cloud folder was not correctly moved, and my config is gone. As I have not moved or replicated the ZFS snapshots, it's lost, but I can live with that.Yeah it was just something to try as a way to troubleshoot if something was keeping the disk from unmounting. Sorry to hear it didnt work.
May 19May 19 Author @MowMdown no way I wanted to blame you. It's just a very complicated topic if you have this issue. Really, finding the problem is not easy.
May 28May 28 I've discovered i have the same issue over the past few updates, since i never reboot otherwise and haven't had any other issues. The last 2 updates I've stopped all VMs and docker containers fully, spun down disks, and then rebooted and both times it still get stuck on the same spot and then kills it and calls it an "unclean shutdown" and finds no array errors (since nothing was running or being written to the array). Reading this thread, I'm still not clear what the issue is though. @sasbro97 did you ever figure it out or did it resolve itself when the cloud folder in your case was moved/deleted?
May 28May 28 Author @john_smith I have no evidence, but I'm pretty sure it had something to do with ZFS datasets/snapshots and, in my case, with the cloud folder within appdata. If you do not depend on these datasets, you could try to delete them and try it again, but I guess this will do nothing. Maybe the dataset itself needs to be wiped and recreated. It's worth a try. After formatting the pool and recreating everything, it works normally again, knocking on wood.
May 29May 29 4 hours ago, sasbro97 said:@john_smith I have no evidence, but I'm pretty sure it had something to do with ZFS datasets/snapshots and, in my case, with the cloud folder within appdata.If you do not depend on these datasets, you could try to delete them and try it again, but I guess this will do nothing. Maybe the dataset itself needs to be wiped and recreated. It's worth a try. After formatting the pool and recreating everything, it works normally again, knocking on wood.How did you determine it was that specific folder? I'm curious to find which is the issue for mine, as I'm also using zfs
May 29May 29 Author While trying everything to stop the array, I found some commands that showed me cache/appdata/cloud is busy. As I said, I have no evidence, but I think this could have been the reason.
May 29May 29 Community Expert 4 hours ago, sasbro97 said:While trying everything to stop the array, I found some commands that showed me cache/appdata/cloud is busy. As I said, I have no evidence, but I think this could have been the reason.Like I think I said, if a path is kept open for read by something, it will not allow the array to fully stop. That's why I suggested using lsof /mnt/cache/ which you might have to drill down like lsof /mnt/cache/cloud/ to find out if there is a process open on that folder. Then you can run pkill -9 <PID> to try and stop it.
June 1Jun 1 I did some testing before shutdown and in my case it looks like its the /mnt/user directory for me show up as a loop in the syslog:root: rmdir: failed to remove '/mnt/user': Device or resource busyafter unmounting it directly (umount -l /mnt/user), the loop blocking stop of the array ended and it stopped
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