hardlinking and deleting milions of small files

[Arkadiusz Miśkiewicz]

Hello.

I'm using rsnapshot to backup big servers (like 5TB fs, 25 000 000 inodes, 
small files - mailboxes in form of maildirs, so each mail is a separate file). 
Backup server - kernel 4.6.3, V4 xfs filesystems.

cp -al for that amount takes about 1.5 day.
rm -rf of hardlinked copy takes another 1.5 day

(and toons of ram for these operations; causing OOM until recent kernels made 
reclaim better, so no more OOM)


Now the weird part - similar operations on ext4 finish in matter of hours.


Are there any possibilities for xfs to improve in these areas? 

From irc #xfs from few months ago the conclusion was that xfs isn't best in 
such operations.

ps. Didn't do scientific comparison (I'm just viewing backup logs of two 
similar mail servers (similar hardware, similar storage size) being backed up 
to single backup server onto two partitions - one with xfs and one with ext4 
on it))
-- 
Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )