I'm using Ubuntu 18.04. My observation for ext4 file system is, once I cross the 90% of data usage the write performance crawls. We have a RAID6 configuration over 12 disks, total 90TB file system. For 81TB we experience 1400 MBps. Post that it drops down to 100 MBps. This drop is very sharp. Is there a way to make it less severe?
I'm exporting my ext4 volume as NFS share. To avoid write crawling after 90% usage, is there any way to force ENOSPACE error on NFS clients post filesystem crosses 90% usage.