[lustre-discuss] question regarding du vs df on lustre

[Einar Næss Jensen]

Hello lustre people.

We are experimenting with lustre on nvme, and observe the following issue:
After running benchmarks and deleting benchmark files, we see that df and du reports different sizes:

[root at idun-02-27 ~]#  du -hs /nvme/
38M     /nvme/
[root at idun-02-27 ~]# df -h|grep nvme
10.3.1.2 at o2ib:/nvme                   5.5T  3.9T  1.3T  76% /nvme


It takes several hours before du and df agrees.

What is causing this?
How can we get updated records for df immediately when deleting files?


Best REegards
Einar