SteveJ-restore-test

Summary : For the delivery of general purpose and wide-scale Compute/Internet Services there now seems to be a definitive hardware organisation for servers, typified by the E-bay "pod" contract . For decades there have been well documented "Design Rules" for producing Silicon devices using specific technologies/fabrication techniques. This is an attempt to capture some rules for current server farms. [ Update 06-Nov-11 : "Design Rules" are important: Patterson in a Sept. 1995 Scientific American article notes that the adoption of a quantitative design approach in the 1980's led to an improvement in microprocessor speedup from 35%pa to 55%pa. After a decade, processors were 3 times faster than forecast.] Commodity Servers have exactly three possible CPU configurations, based on "scale-up" factors: single CPU, with no coupling/coherency between App instances. e.g. pure static web-server. dual CPU, with moderate coupling/coherency. e.g. web-s...

In Networking, the 'performance objects' are links, usually end-to-end, consisting of many elements - like ethernet segments, switches, routers/firewalls, long-distance circuits and security scanner devices, laid on top of Telco/backbone services that provide dynamic and asymmetrical routes. The most frequently used measure is 'ping' time - ICMP “echo request” packets, often 64 bytes long. Firewalls, routers and underlying networks filter/block classes of traffic, implement traffic & flow rules and attempt "Quality of Service". There are many common rulesets in use: blocking 'ping' outright for 'security reasons'. Stops trivial network scanning. QoS settings for different traffic classes. VoIP/SIP gets high priority, FTP traffic is low, your guess on HTTP, DNS, time (NTP) and command line access - SSH, Telnet, ... traffic profiling on IP type (ICMP, UDP, TCP) and packet size (vs link MTU). traffic prioritisation based on source/destination....