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– …
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