why is a new xfs filesystem fragmented?
It's hard enough trying to guess the size for physical and logical extents but then....
My controller is old, a 3ware 9650SE 8 port, with 8x2TB drives
I have one 10TB volume group, with PE Size 32MB.
Several logical volumes, music, photos, tv, dvd, bluray, source, and scratch. Since each is different size, with different avg file size, and growing at a different rate.
I bought a new LSI 9260-8i and essentially mirrored the previous layout, making the new PE size larger 64MB.
I then copied all data from old to new using rsync --archive
Just for kicks I check the new Bluray, where avg file size is 40GB and fragmentation is exactly the same as it was on the old controller.
xfs_db -c frag -r /dev/mapper/mainvg-bluray
actual 557, ideal 107, fragmentation factor 80.79%
The old school perfect defrag was to backup a fs to tape and then restore from tape, leaving a perfectly contiguous fs.
Why did that not happen in my case?