I've encountered this (or similar) issue on production.
We had C++ system that wrote temporary files to /tmp when printing, /tmp was cleared on system startup, it worked ok for years, but the files accumulated. At some point it started to randomly throw file access errors when trying to create these temporary files. Not for each file - only for some of them.
Disk wasn't full, some files could be created in /tmp, others couldn't, it turned out after a few days of tracking it, that filesystem can be overwhelmed by too many similary named files in one directory - and it can't create file XXXX99999 even if there's is no such file in this directory, but it can create files like YYYYY99999 :)
I just love such bugs where your basic assumptions turn out to be wrong.
We had C++ system that wrote temporary files to /tmp when printing, /tmp was cleared on system startup, it worked ok for years, but the files accumulated. At some point it started to randomly throw file access errors when trying to create these temporary files. Not for each file - only for some of them.
Disk wasn't full, some files could be created in /tmp, others couldn't, it turned out after a few days of tracking it, that filesystem can be overwhelmed by too many similary named files in one directory - and it can't create file XXXX99999 even if there's is no such file in this directory, but it can create files like YYYYY99999 :)
I just love such bugs where your basic assumptions turn out to be wrong.