Courtesy: BackupPC Wiki
Modern Dual Core processors yield good performance (core duo, core2 duo, athlon x2, opteron dual core). Lesser CPUs can still make good BackupPC servers but be aware of heat issues on Pentium4 processors. Also, compression and multiple concurrent backups will perform better with a faster CPU. A faster CPU also enables bzip
1-2GB is typically sufficient.
Recommended Hard Disks
Disk selection is dependent on level of use, volume of data being backed up, backup frequency, and the number of backups you plan to keep.
A basic BackupPC setup can use a single IDE or SATA disk but should have a mirrored disk in a RAID1 setup to avoid disaster with drive failure.
To reach “Enterprise Level Backups”, SCSI or SAS drives in a hot-swappable RAID5 or RAID6 setup, redundant power, any modern CPU, and 2 or more GB of RAM is ideal.
Recommended Disk Configuration
RAID1, RAID5, ZFS ZRAID, software RAID via Linux (but software RAID via cheap IDE raid cards is NOT recommended). Cheap RAID cards are hard to replace when they fail and make it nearly impossible to recover data. Linux software RAID and ZFS ZRAID are very easy to recover and perform well, sometimes rivaling hardware RAID cards. For x86 hardware RAID cards, 3ware has many recommenders. Adaptec slightly fewer. Some hardware OEMs also include acceptable hardware raid (Dell PERC–generally rebranded Adaptec or MegaRaid chips, for instance). Just ensure your hardware RAID card actually is hardware RAID.
On any operating system, please choose your filesystem wisely. Choose a stable filesystem for which you have (or can gain) a familiarity with recovery tools. Regardless of filesystem choice, please ensure that you allocate enough inodes when you create the filesystem. With its use of hardlinks, BackupPC has been known to use all inodes on some filesystems created with default arguments. Obviously, be certain to choose a filesystem capable of handling your disk’s capacity. http://en.wikipedia.org/wiki/Comparison_of_file_systems
On Linux, EXT2, EXT3, ReiserFS and XFS have been used with good results. Exotic or cutting edge filesystems may come with unwanted instability. Use your filesystems within LVM if available. LVM allows for powerful volume management.
On Solaris, UFS is a very good general purpose filesystem but ZFS may be a better choice. ZFS includes built in volume management, build in compression, snapshots, migration, and filesystem level remote mirroring.
On other Unixes, UFS may be the only option, but ZFS is now available for virtually all of the BSDs.