[Dovecot] XFS vs EXT4 for mail storage

[Michael Weissenbacher]

Hi Marcus!

> Should I go with EXT4? Or XFS with just the defaults? Or XFS with one or more tuned parameters?
...
> I'm not using quotas, and understand what inode64 does and am fine with
> that, but what I'm still unsure of for a VM environment is the delaylog
> and nobarrier options.

I've been using XFS for many years now and i strongly recommend it for 
anything besides /boot. Considering a virtual environment i would 
strongly suggest NOT using nobarrier (i.e. use barrier). You can run 
into big trouble should the system ever lose power. In fact the only 
time i ever managed to damage a XFS filesystem on all those years was 
inside a VM and with the nobarrier option on and the UPS died (and yes 
the server had a functioning BBS battery attached to the RAID). The 
delaylog option can be recommended hands-off, since it speeds up 
metadata operations considerably (up to 10 times faster!). And for your 
last quesion, stay with the defaults when doing mkfs.xfs, optimizing for 
stripe width and stipe size and all those other options really only make 
sense on a physical machine.

hth and good luck,
Michael