[lustre-discuss] lester on mds with low memory

[Alexander Oltu]

Hi,

We are trying to run lester (https://github.com/ORNL-TechInt/lester) on MDS with low memory and about 41M files in Lustre filesystem. There is an extensive amount of file operations going all the time on the filesystem.

This is the current memory situation on MDS:

cat /proc/meminfo |egrep 'MemTotal|MemFree|Buffers|Slab'
MemTotal:       16533620 kB
MemFree:         1025312 kB
Buffers:        12591976 kB
Slab:            1391508 kB

By dropping caches we can make maximum available memory of 1,5GB. When we run Lester it gets killed by OOM (System has no swap).
I tried using UNIX IO manager and decreasing group and dir readahead, but there is still not enough memory to finish scan.

Anyone has any experience with running lester on low memory? Will appreciate any suggestion. (There is no option to add physical RAM).

Thanks,
Alex.