II. Definitions
- See Computer Network for Switches and Routers
- Uninterruptible Power Supply (UPS)
- http://en.wikipedia.org/wiki/Uninterruptible_power_supply
- Backup power storage for electronic devices providing up to 30 minutes of backup power supply
- Server Rack
- Shelving unit that holds servers (computer units)
- Standard rack size (42 U), has enough space to hold 42 units
- Typically holds 15-30 servers/rack (limited by power, cooling, switch space)
- A single server rack may have impressive requirements for weight, power and cooling
- May weigh more than 2000 pounds
- Use up to 10-20 kW power
- Require 3-6 tons cooling (36-72k BTU/h, 11-22 kW)
- Server Farm
- Collection of servers and their racks, switches, power supplies and UPS systems
- Data Center
- Facility that houses one or more server farms
- Along with support systems (power generation and backup, physical security, cooling/HVAC)
- A Data Center may contain hundreds of racks and use several megawatts of power
- Facility that houses one or more server farms
- Data Closet
- Typically one data closet per floor of a facility that houses the networking equipment and cables
- Data closets require locks and security to prevent unauthorized access, data theft, network tampering
- Data closets should consider cooling (HVAC) concerns
- Cable Plant
- Topographical map demonstrating the layout of a network with cabling
- Demonstrates cable connections
- Client machines (e.g. desktops) to networking equipment in data closets and onto data centers
- Data Cables
- Cables interconnect the Computer Network, between client machines, data switches, data closet
- Among the most difficult and expensive network infrastructure components to maintain
- Accumulation of outdated (inadequate bandwidth) and inactive (replaced) cables
- New laying of cables risks damaging existing infrastructure to critical areas (e.g. ICU, OR)
- New cabling must take into account fire codes, and infection isolation barriers (e.g. holes between rooms)
-
Patch Panels
- Ethernet cable termination point at a panel typically inside a data closet
- Each ethernet cable port should be labeled for source
- Dual-Homed Switch Routers
- Maintains two network interfaces or connections to provide redundancy in case one interface fails
- May be implemented at multiple network levels (building floor, building, network backbone to the data center)
III. Background: Data Center Reliability Classes or Tiers
- http://en.wikipedia.org/wiki/Data_center
- Tier 1 (basic)
- Power and cooling have a single path
- Allows for 99.671 availability (28.8 hours of downtime per year)
- Tier 2 (redundant)
- Power and cooling still have a single path, however has redundant capacity
- Allows for 99.741 availability (22.7 hours of downtime per year)
- Tier 3 (concurrently maintainable)
- All IT equipment is dual powered
- Multiple independent distribution paths
- Infrastructure is maintainable while in operation
- Allows for 99.982 availability (94 minutes of downtime per year)
- Tier 4 (fault tolerant)
- Dual, independently powered cooling equipment (full HVAC systems)
- Site with independent power storage
- Allows for 99.995 availability (26 minutes of downtime per year)