Currently Lustre enabled user/group accounting in default, in our testing, we found
that with these extra object accounting, there is big overhead especially for metadata
intensive workload, there will be more overhead with project quota enabled.(Numbers
will be attached later)

Ideally, we could reach similar performance number with/without quota.

There are some Kernel and Ext4 patches merged by Linux upstream which could
significantly improve the quota performance, it will be good to have them in Lustre
RHEL7.