II. Definitions

  1. See Computer Network for Switches and Routers
  2. Uninterruptible Power Supply (UPS)
    1. http://en.wikipedia.org/wiki/Uninterruptible_power_supply
    2. Backup power storage for electronic devices providing up to 30 minutes of backup power supply
  3. Server Rack
    1. Shelving unit that holds servers (computer units)
    2. Standard rack size (42 U), has enough space to hold 42 units
      1. Typically holds 15-30 servers/rack (limited by power, cooling, switch space)
    3. A single server rack may have impressive requirements for weight, power and cooling
      1. May weigh more than 2000 pounds
      2. Use up to 10-20 kW power
      3. Require 3-6 tons cooling (36-72k BTU/h, 11-22 kW)
  4. Server Farm
    1. Collection of servers and their racks, switches, power supplies and UPS systems
  5. Data Center
    1. Facility that houses one or more server farms
      1. Along with support systems (power generation and backup, physical security, cooling/HVAC)
      2. A Data Center may contain hundreds of racks and use several megawatts of power
  6. Data Closet
    1. Typically one data closet per floor of a facility that houses the networking equipment and cables
    2. Data closets require locks and security to prevent unauthorized access, data theft, network tampering
    3. Data closets should consider cooling (HVAC) concerns
  7. Cable Plant
    1. Topographical map demonstrating the layout of a network with cabling
    2. Demonstrates cable connections
      1. Client machines (e.g. desktops) to networking equipment in data closets and onto data centers
  8. Data Cables
    1. Cables interconnect the Computer Network, between client machines, data switches, data closet
    2. Among the most difficult and expensive network infrastructure components to maintain
      1. Accumulation of outdated (inadequate bandwidth) and inactive (replaced) cables
      2. New laying of cables risks damaging existing infrastructure to critical areas (e.g. ICU, OR)
      3. New cabling must take into account fire codes, and infection isolation barriers (e.g. holes between rooms)
  9. Patch Panels
    1. Ethernet cable termination point at a panel typically inside a data closet
    2. Each ethernet cable port should be labeled for source
  10. Dual-Homed Switch Routers
    1. Maintains two network interfaces or connections to provide redundancy in case one interface fails
    2. May be implemented at multiple network levels (building floor, building, network backbone to the data center)

III. Background: Data Center Reliability Classes or Tiers

  1. http://en.wikipedia.org/wiki/Data_center
  2. Tier 1 (basic)
    1. Power and cooling have a single path
    2. Allows for 99.671 availability (28.8 hours of downtime per year)
  3. Tier 2 (redundant)
    1. Power and cooling still have a single path, however has redundant capacity
    2. Allows for 99.741 availability (22.7 hours of downtime per year)
  4. Tier 3 (concurrently maintainable)
    1. All IT equipment is dual powered
    2. Multiple independent distribution paths
    3. Infrastructure is maintainable while in operation
    4. Allows for 99.982 availability (94 minutes of downtime per year)
  5. Tier 4 (fault tolerant)
    1. Dual, independently powered cooling equipment (full HVAC systems)
    2. Site with independent power storage
    3. Allows for 99.995 availability (26 minutes of downtime per year)

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