On 2014-08-21 14:02, Anton Aylward wrote:
On 08/20/2014 10:16 PM, Carlos E. R. wrote:
Ah, but you forget the huge number of inodes used
Not an issue with the b-tree-like FS such as ReiserFS, XFS and BtrFS.
Yes, it is is an issue on btrfs, as I demonstrated it with a test that I
published here. The filesystem crashes completely if you create "too
many" small files, and speed diminishes hugely before that. There is an
unsolved bugzilla on it.
XFS adjusts the equivalent of inodes dynamically, it adapts, but
nevertheless, it has a limit. The recommendation is to tune the
filesytem, on creation time, for many small files.
ext2/3/4 has a fixed number of inodes, but it can also be tuned for a
large number of small files.
Reiserfs is the only filesystem that has no issues with the situation,
and is way faster than the rest (in this situation). But development is
stuck, and it scales badly (only one thread is used for all the reiserfs
partitions you have, regardless of the number of cores you have). It is
possible that it disappears from the distribution not far in the future
- in 13.1 you can not create a reiserfs in YaST, for instance, support
has already been removed there.
Nor is the 'growth' of the size of the
directory & compacting it nor, if
you set up the options to start with, sorting huge directories.
It is an issue in the sense that it impacts performance a lot. You only
need to run tests on large mail folders using several formats, and
compare. Some workloads run faster on maildir, and some on mbox.
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 "Bottle" at Telcontar)