What is it?
Servers are specially built computer systems designed to run 24/7, usually with redundant parts to keep the system running in the event of a failure. These redunant systems include; multiple power supplies, multiple CPUs, and multiple Hard Drives using RAID system.
Why not a PC?
Many small businesses will use a PC to act as a server, although this will work you will not have any of the redundancies or improved performance a server was built to provide. One primary example of this is the RAID system, RAID stores data to multiple drives at the same type, this protects against a drive failure and improves drive performance. PCs are also designed for basic tasks and to be used 8 hours a day. A server needs to run tasks throughout the day, updates or backups at night, many users accessing data, etc. The PC will wear out substantially faster then the server.
Redundant Array of Independent Disks (RAID) is used to protect against drive failures and sometimes improves performance. There are multiple types of RAID including…
RAID0 – Two or more drives are combined to create one large storage with NO protection. Great to create large storage space, but does not give any improved performance or failure protection, if one drive fails all data is lost.
RAID1 – Two drives are used to create two copies of all data. One drive can be lost with no data loss. There is also improved read speed since both disks can be used to access data. However, write speeds are reduced since the data must be written twice.
RAID5 – Three or more drives are used. This writes the data to a disk and information on how to recover that data to another disk. If a single drive fails no data is lost. Read performance is slightly better then RAID1.
RAID10 – four drives are needed. This is a combination of RAID1 and RAID0. In theory you could loose two drives, but only if it is the correct two drives.
RAID50 – six or more drives are needed. This is a combination of RAID5 and RAID0.
RAID6 – Four or more disks are required, this is the same as RAID5 but with an extra drive for protection. In this setup two drives can fail without data loss.