Ric Wheeler wrote:
In our testing with f12, I build a 60TB ext4 file system with 1 billion small files. A forced fsck of ext4 finished in 2.5 hours give or take a bit :-) The fill was artificial and the file system was not aged, so real world results will probably be slower.
fsck time scales mostly with the number of allocated files in my experience. Allocated blocks (fewer very large files) are quite quick.
What kind of machine did you use?
With 60TB a simple allocation bitmap for 4k-blocks takes almost 2GB; and this is just to detect free space or double allocation of blocks. Wow.