Projected volume size is around 1TB,. Filesystem should perform fast when dealing with LOTS of files in every folder.
Snapshots support would be great, for backup purpose, but not compulsory.
It will be created over a hardware RAID 0+1 system, but I hardly doubt this will be an issue.
While I haven't checked out ext4 yet, I'm using xfs with LVM almost everywhere.
You get the snapshots, you get online partition growing, and instant fsck if you do crash. When my mail spool fills up, I'm happy to know its a 30 seconds procedure to fix - assuming your LVM volume group has some free space in it.
LVM running ReiserFS - managed a server storing in the region of 20,000,000 quarantined messages and never skipped a beat.
Plus for reasons I never worked out, the LVM on hardware RAID was faster than native file system access.
There is the potential for an issue with flock, non syncronous updates and Reiser but I never actually ran into it in the best part of 3 years.
I discourage ReiserFS for panic under heavy load:
REISERFS: panic (device Null superblock): vs-7042: entry_points_to_object: entry
must be visible
ReiserFS works quite realiably until it is stressed with many concurrent accesses. You can read about it here.
Just now I have Maildir (around 200GB) on ReiserFS. During last two days FS crashed two times and I'm looking for a way to resolve this problem (seems like using kernel 2.6.25.4 helps). Later I will try to migrate to JFS or XFS.
ReiserFS seems unmaintained and for sure have existing bugs. Its speed does not compensate for its problems. It is not realiable solution.
