UltimateDefrag 6 vs xfs_fsr

UltimateDefrag 6 has no write-up on Specifiction yet; its figures are above.

xfs_fsr is a free Linux utility in the xfsprogs project that reorganizes mounted XFS filesystems one file at a time. It copies a target file to temporary storage, then atomically exchanges the data extents of the original and temporary files. With no arguments, it chooses files with the largest extent counts and attempts the top 10% on each pass. A default run lasts up to two hours and records its stopping point for later resumption. You can name filesystems or individual files, with one pass through each target. Targets must be mounted read-write; entries without that option are skipped. Files mapped in memory and files marked no-defrag are not processed. Reorganization needs enough free space to copy the target, with space less fragmented than the original. On quota-enabled systems, the owner also needs sufficient remaining file quota. The manual says system partitions generally do not need this utility and warns that moving bootloader files can prevent booting unless lilo is rerun before reboot.