[SERVER-30494] Running mongod server with empty mongod.lock file Created: 03/Aug/17 Updated: 27/Oct/23 Resolved: 21/Aug/17 |
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| Status: | Closed |
| Project: | Core Server |
| Component/s: | Concurrency, Storage, WiredTiger |
| Affects Version/s: | 3.2.10 |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Major - P3 |
| Reporter: | Marek Skalický | Assignee: | Mark Agarunov |
| Resolution: | Gone away | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Environment: |
Linux based OS |
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| Attachments: |
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| Operating System: | ALL |
| Participants: |
| Description |
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I have running mongod 3.2 with --dbpath on NFS. When I run mongod -f /etc/mongod.conf then mongod is running and accepting connections, but file `/var/lib/mongodb/data/mongod.lock` is empty. How it is possible? I am trying to figure out how to reproduce it, but for now what could be reason of this odd behavior? Content of /etc/mongod.conf
File with server output is attached. |
| Comments |
| Comment by Mark Agarunov [ 21/Aug/17 ] |
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Hello mskalick, Thank you for the additional information. I agree that this doesn't appear to be a bug in MongoDB itself, so I have closed the ticket. If new information comes to light about this issue, please let us know and we will reopen the ticket. Thanks, |
| Comment by Marek Skalický [ 21/Aug/17 ] |
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Hi, We get further with this issue. It seems that this is a Linux Kernel issue. It appears when mandatory locking is set up on NFS server - then writes from a process are conflicting with a fcntl lock set by the same process. This series of patches fixes this problem - https://www.spinics.net/lists/linux-nfs/msg60358.html . I think it is merged into kernel 4.10. We reproduced this with RHEL7. Not sure if this should be mentioned somewhere in your documentation. This bug can be closed from my point of view as bug is not in MongoDB itself. |
| Comment by Mark Agarunov [ 15/Aug/17 ] |
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Hello mskalick, Thank you for the report. Unfortunately there isn't anything in the log file to point to a cause for the empty lock file and I have not been able to reproduce the behavior. It is possible that the lock file was cleared if a new mongod process was started while another was stopping, but that is purely speculation. Is this behavior still present and an issue for you? Thanks, |