thanks for the info , i already know it, i was planning to use three fs anyway but it's pity for sure.
creation of ext4 fs is under 3 min for 12To
and a forced check 2min 30 s ( over a clean fs)
for the choice xfs/jfs , i don't know well JFS but i got performance trouble with xfs under charge...
Amount of total storage: 60TB (the older system will be published soon)
Titanic: 40TB
Case: Supermicro, SuperChassis 846A-R900B
PSU: 900w include in the case
Motherboard: X8DTi-LN4F
CPU: 2xE5620
RAM 12x4GB DDR3 ECC Registered 1333MHz Kingstom
GPU no
Controller Cards ARC-1680i-24
Optical Drives...