i'm building an email system and considering some filesystem that support online-resize, safe when power-outage, and does not restrict number of files per directory(or at least can hold some millions file per directory)
I want to know which filesystem is best for this situations. Can you help me,pls?
Thanks in advance!
PS: i'm layering for my email storage as:
Layer-3: Filesystem(XFS,JFS,Btrfs,Reiser4,…) on top of drbd(/dev/drbd0)
Layer-2: DRBD(Dual-primary mode) on LVM2's logical volume
Layer-1: LVM2 on physical volume(/dev/sdc,/dev/sdd,…)
Layer-0: physical volume(sdc,sdd,…) is Hardware RAID10(with "Write-cache mode" is enabled) (each "physical volume" actually is 4 HDD)
Another question: Do you see something wrong in my design?
Edited: i'm using Ubuntu 12.04 LTS with 3.2 kernel.
Best Answer
XFS has been a reliable workhorse for me for many years. The mail system I'm talking about is happily running Cyrus IMAP server with 50 000+ accounts (at peak it was nearly 100 000 accounts) and about 300 000 mail boxes. There are tens of millions of mail files. Everything works smoothly and server load is mostly idle.
But... couple of million of files per directory? What kind of mail system are we talking about? XFS might handle that somehow, but no file system has been designed for that kind of behaviour.