Seeking guidance on detecting mount point inactivity

[Richard]

Hi,

On 25/06/2026 16:37, Ali Nasrolahi wrote:
> Hello everyone,
> 
> I am working on a  problem involving managing some number of filesystem 
> mounts (~1000+) and determining when a mount becomes inactive to do some 
Honestly this does not sound like a good/sane setup to start with. Maybe 
zooming out and solving the overall requirement with a different setup 
might be smarter.

> maintenance.
> To be specific, the goal is to detect when a mounted filesystem has no 
> remaining active file usage, and after it remains inactive for some 
> period (e.g. 10 seconds),
> transition it into a state where new file opens are blocked so that 
> maintenance operations can safely proceed.
> It must handle concurrent access from arbitrary applications, so 
> correctness under races is quite challenging.

Why do you care about the filesystem level? If this is about device 
maintendance device activity might be more relevant than fs activity. 
(Remember there is caching and lots of other abstraction). It might also 
be easier to track bio requests for a specific device on the device level.

I don't know tools from the top of my head but I'm sure there are files 
for this in /sys/. There is also iotop and you can see its source code 
where it gets its info from. I'd also recommend reading brendan greggs 
System Performance book. It has 2 chapters on disks and block I/O, I'm 
sure you'll find good diagnostic tools there.

Best,
-- Richard