Original Message from: Burakov, Anatoly [mailto:anatoly.burakov@intel.com] 

I just realized that, unless you're using --legacy-mem switch, one other 
way to alleviate the issue would be to use --single-file-segments 
option. This will still store the fd's, however it will only do so per 
memseg list, not per page. So, instead of 1000's of fd's with 2MB pages, 
you'd end up with under 10. Hope this helps!

Hi Anatoly,

Thanks for the update and suggestion. We did try using --single-file-segments previously. Although it lowers the amount of fd's allocated for tracking the segments as you noted, there is still a problem.

It seems that a .lock file is created for each huge page, not for each segment. So with 2MB pages the glibc limit of 1024 fd's is still exhausted quickly if there is ~2GB of 2MB huge pages.

Edwin can provide more details from his testing. In our case much sooner, as we already use >500 fd's for the application, just 1GB of 2MB huge pages is enough to hit the fd limit due to the .lock files.

Thanks.