Server Systems Administration

Types of Servers

• Small Servers– Usually are PCs– Need a PC Server Operating System (SOS)

such as Microsoft Windows Server, Novell NetWare, LINUX

• Large Servers– Usually use Workstation Servers– Usually run UNIX

Symmetric Multiprocessing (SMP)

• PC or workstation can have multiple microprocessors

• Work is shared among the microprocessors through symmetric multiprocessing (SMP) to increase overall speed

• However, if you have N microprocessors, your server is not N times faster than a single-microprocessor server because of problems in assigning work evenly

RAID• Redundant Array or Inexpensive (or

Independent) Drives– RAID controller controls multiple small inexpensive

disk drives

– Reads and writes in parallel for higher speed despite low-cost drives

RAID• Redundant Array or Inexpensive (or

Independent) Drives– Information is stored redundantly

– If one disk fails, lose no information

– Drives may even be hot-swappable• Do not have to turn off computer to replace

Server Farms• In large sites, one server is not enough

– Have several, even hundreds of servers– Called a server farm– Many PC servers may be more cost-effective

than fewer workstation servers

ServerFarm

Server Farms• Load Balancing Approach

– Router or other device sends requests to servers based on load

Server Farms• Server Clustering Approach

– Act as a single server without an external load balancer

Server Farms• Reliability

– If one server’s hardware fails, operation continues without interruption

– However, software failures often take down all servers simultaneously

Server Configuration

• When Server Operating System is Installed, it Must be Configured– Complex task with many steps, many of which

require you to have conceptual knowledge

– Requires training

– Valuable skill

Ongoing Work

• Server Systems Administration is Labor-Intensive on a Continuing Basis– Assigning and changing rights for users– Backup– …