I would like to know, from more experienced people, what would be the best choice of file system to use for a file server having more than 20TB of hard disks. Personally I always used EXT3 (back in the days) and EXT4 (since available) [and once ReiserFS 3 though it caused many data corruption] on my personal computers and on the "little servers" BOOT and ROOT disks.
However as EXT4 tools (though not EXT4 itself) is limited to 16TB partitions this may not be my best bet. Distribution will be Debian 6.0 (Squeeze) and / or Gentoo (latest version), so kernel should be pretty recent (on Debian at least with backports), meaning linux kernel >= 2.6.32.
File server will be used for maily three purposes (and separated partitions as well, because the purpose is to keep data "safe" and don't really care much of overhead). All disks are though to be encrypted using LUKS:
- Media, downloads and local debian repository [I have at least 6 machines running Debian] >20TB (maybe further separation between Media, Downloads and Debian repository)
- Data (Documents, Photos, ...) ~ 4TB SAFE (meaning raid1 or raid6 + backup disk)
- Backups >= 20 TB for backups of other computers in my gigabit lan (can you suggest a software that backups the entire OS even if it's windows, BackupPC says it does that, any alternatives ?)
Fast speeds are not really necessary (concurrent accesses: maximum to 2 or 3 large files, say videos), even if it's "just" 200MB/s reads from a 10 HDD Raid6 I can live with that.
In summary I look for a reliable, scalable (i.e. easily expandable) filesystem that supports more than 20TB / partition. The safer and reliable the FS is, the better. Hardware employed will be at least a quad core (amd x4 630 or intel i5-2500k) and plenty of RAM (>8GB, maybe >16GB) so hardware requirements should be met.
My PCs / Server will be connected to an UPS (Uninterrupted Power Supply) in case of power outage Might do media and backups on separate machines as well (i.e. two servers).