Samsung vs WD

If you're concerned about uptime and reliability of a server then you should be using redundant RAID and Enterprise-class drives instead of consumer drives. Enterprise-class drives are built to higher tolerances, typically have more extensive ECC codes and include RAID-optimized firmware.

For example, on this list of Western Digital SATA drives, the Enterprise-class drives are RE2/RE3/RE4 series.

Remember that RAID is not a backup - you still need to have a plan for backing up your data to external media.