[PATCH] xfs_db: defang frag command

Eric Sandeen
2016-05-11T19:41:32Z

Too many people freak out about this fictitious "fragmentation
factor." As shown in the fact, it is largely meaningless, because
the number approaches 100% extremely quickly for just a few
extents per file.

I thought about removing it altogether, but perhaps a note
about its uselessness, and a more soothing metric (avg extents
per file) might be useful.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/db/frag.c b/db/frag.c
index 36bb689..e11b140 100644
--- a/db/frag.c
+++ b/db/frag.c
@@ -172,6 +172,10 @@ frag_f(
answer = 0.0;
dbprintf(_("actual %llu, ideal %llu, fragmentation factor %.2f%%\n"),
extcount_actual, extcount_ideal, answer);
+ dbprintf(_("Note, this number is largely meaningless.\n"));
+ answer = (double)extcount_actual / (double)extcount_ideal;
+ dbprintf(_("Files on this filesystem average %.2f extents per file\n"),
+ answer);
return 0;
}