Maildirs on AWS EFS

[Rodolfo Gonzalez]

Hello,

AWS released one month ago a EFS system with administered life cycle, 
which means that files not accessed in the last 30 days are moved to a 
lower cost storage tier. Currently I hold my e-mail, delivered to 
Maildir++ folders by postfix and retrieved with Dovecot, in standard EBS 
volumes. This has the disadvantage that I need to allocate more than 
enough space to ensure that the volume won't get filled too soon. And 
this costs. Changing to standard EFS wasn't an option, since it's way 
more expensive than EBS. But, with the new system, costs are lower.

I just have a doubt in the technical side: is it safe to have the email 
in EFS? I've read experiences about storing in S3 and using a driver to 
mount the bucket, and it seems that it's not a very good option. But EFS 
works like NFS4. Does anyone have experience mounting an EFS to store 
maildirs?

Thanks in advanced,
Rodolfo.