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After running the command umount /mnt, the following error message is displayed:
umount: /mnt: device is busy.
What is a common reason for this message?
Suggested Answer: C
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37 comments · newest first
PH
Phil
11 months ago
The kernel flushing writes is also a possibility, but less common.
VA
Valentin
11 months ago
Wait, really? I didn't know that could happen!
VA
Valentin
11 months ago
I thought it could be a symlink issue too.
DA
Dahlia
12 months ago
Totally agree, that's usually it!
LE
Leonora
12 months ago
Common reason? A user has a file open in /mnt.
MI
Micah
12 months ago
I vaguely recall something about processes and the kernel thinking a file is about to be opened. E sounds familiar, but I’m not confident.
EL
Elfrieda
1 year ago
I practiced a similar question where a symlink caused issues. Could it be C? I feel like that might be a possibility.
SH
Shaniqua
1 year ago
I think the kernel flushing writes could be a reason too, but that seems less likely than a user having a file open.
TA
Tamesha
1 year ago
I remember something about processes holding onto files, so maybe it's B? But I'm not completely sure.
PR
Precious
1 year ago
This is a classic Linux systems administration question. I'm pretty confident I know the common reasons for a "device is busy" error when trying to unmount. I'll quickly review the options and select the most likely answer.
JO
Jonelle
1 year ago
Okay, I've got a strategy for this. The key is to think about what could be holding a reference to the mounted device, preventing it from being unmounted. I'll carefully consider each option and try to eliminate the less likely ones.
ER
Eric
1 year ago
Hmm, I'm a bit unsure about this one. The error message doesn't give me a lot of context, so I'll have to think through the possible reasons why the device could be busy. I'll make sure to read the options closely.
EL
Elza
1 year ago
This seems like a pretty straightforward question. I'll carefully read through the options and think about common reasons why a device might be busy when trying to unmount it.
AP
Apolonia
1 year ago
I'm a bit confused by the options here. I'll need to think through the different ways to approach a layout change like this.
TI
Tijuana
1 year ago
I'm a little confused by this question. Scoping to host names doesn't seem relevant, since we're targeting specific containers. I'm leaning towards option B, scoping to namespaces, but I'm not 100% sure.
LE
Lemuel
1 year ago
I bet the person who wrote this question was chuckling to themselves the whole time, trying to come up with the most absurd options possible.
TA
Tamar
1 year ago
C) Another file system still contains a symlink to a file inside /mnt.
AD
Adela
1 year ago
B) A user has a file open in the /mnt directory.
CE
Celestine
1 year ago
A) The kernel has not finished flushing disk writes to the mounted device.
NO
Nobuko
1 year ago
The kernel thinking a process is about to open a file in /mnt for reading? That's got to be the silliest reason I've Nobukor heard for this error message.
HE
Heike
1 year ago
The files in /mnt being added to the locate database? That's a new one for me. I wonder if the exam writers are just trying to trick us with that one.
MI
Mitsue
1 year ago
C) Another file system still contains a symlink to a file inside /mnt.
DO
Dortha
1 year ago
B) A user has a file open in the /mnt directory.
JO
Jospeh
1 year ago
A) The kernel has not finished flushing disk writes to the mounted device.
LI
Lillian
1 year ago
Another file system with a symlink to a file inside /mnt? That's an interesting possibility, but it doesn't seem as common as the first two options.
AL
Aliza
1 year ago
C) Another file system still contains a symlink to a file inside /mnt.
LE
Lettie
1 year ago
B) A user has a file open in the /mnt directory.
RY
Ryann
1 year ago
A) The kernel has not finished flushing disk writes to the mounted device.
FR
Frank
1 year ago
Hmm, a user having a file open in the /mnt directory makes sense too. I need to be more careful about that when working with mounted file systems.
LY
Lynna
2 years ago
The kernel not having finished flushing disk writes sounds like the most likely reason to me. I've encountered this issue before when trying to unmount a busy device.
TH
Thomasena
1 year ago
That makes sense. The kernel could be waiting for that process to finish before unmounting.
TE
Tegan
1 year ago
A user likely has a file open in the /mnt directory.
LA
Lai
1 year ago
E
JE
Jeffrey
1 year ago
A
OL
Olga
2 years ago
I'm not sure, but I think it could also be E) The kernel thinks that a process is about to open a file in /mnt for reading.
AL
Alisha
2 years ago
I agree with Glennis, it makes sense that the device is busy because a file is open in /mnt.
GL
Glennis
2 years ago
I think the answer is B) A user has a file open in the /mnt directory.