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CN2 VPS

16 Feb 2017 • Leave Comments

Virtualization

OpenVZ/XEN/KVM

OpenVZ

  1. OpenVZ is a half virtualized technology at OS-level with limitations. Each VPS is actually a guest operating system container and shares the same underlying host operating system but still operates as secure, isolated environment.
    1. We cannot make any kernel level modifications inside the VPS. The VPS's on the host share the host kernel.
    2. Host can easily be over-subscribed. Hosting providers can and do host 20+ OpenVZ virtual machines on a system with 12 GB of ram. Each VPS has 1 GB of ram "assigned" to it. Not all systems use 1 GB all the time, so the system "robs Peter to pay Paul" when a VPS does need all its memory. It will allow the VPS to access its assigned amount of ram. However if none is available due to other VPS's using it, contention can get bad and things slow down.
    3. Openvz is better when you want to run a mass of linux VMs and need to be able to flexibly allocate resources between them. Since the systems are all using the same file system, kernel and memory space, a container dosen't need memory for its exclusive use.

XEN

  1. OpenVZ is generally oversells to take advantages of unused resources, while XEN cannot, thus slightly more costly and they call XEN VDS (Virtual Dedicated Server) rather than VPS (Virtual Private Server). If you running gameserver for example, XEN is a MUST! KVM won't be as fast as XEN.

KVM

  1. Your host OS has to be Linux but it supports Linux, Windows, Solaris, and BSD guests. It runs on x86 and x86-64 systems with hardware supporting virtualization extensions (Intel VT or AMD-V). It consists of a loadable kernel module, that provides the core virtualization infrastructure and a processor specific module.

ChinaTelecom 163 to CN2

  1. ChinaNetNextCarryingNetwork (CN2)

    Isolated from the old ChinaNet/China163, CN2 is ChinaTelecom's newly built highly qualified backbone to serve coporate clients.

  2. MTR - My TraceRoute, an Excellent network diagnostic tool

    MTR represents an evolution of traceroute with a greate data sample. It combines the functions of the traceroute and ping programs in one network diagnostic tool.

    Because MTR provides an image of the route traffic takes from one host to another, you can think of it as a directional tool. Furthermore, the route taken between two points on the Internet can vary a great deal based on location and the routers that are located upstream of you. For this reason it is often recommended that you collect MTR reports in both directions for all hosts that are experiencing connectivity issues, or as many hosts as possible.

    ~ $ mtr -rtw [destination_host]

  3. Bi-directional CN2

    It's really important to mtr from VPS to PC since that's the daily traffic flow direction!

  4. An example of mtr output:

    zhtux ~ # mtr -rw 220.173.118.215
Start: Thu Feb 16 20:25:53 2017
HOST: zhtux           Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- 192.168.0.1      0.0%    10    3.0   2.1   1.1   6.2   1.5
  2.|-- hz-dns90         0.0%    10    4.8   4.0   2.5   7.5   1.3
  3.|-- 172.16.203.253   0.0%    10    3.9   4.5   3.5   6.4   0.8
  4.|-- hz-dns90         0.0%    10    3.7   3.8   1.9   8.1   2.1
  5.|-- hz-dns90         0.0%    10    6.0  12.1   5.2  40.8  10.8
  6.|-- hz-dns90        20.0%    10   23.7   8.6   3.0  23.7   6.9
  7.|-- 101.4.114.229   50.0%    10    6.0  15.6   6.0  32.9  10.7
  8.|-- 101.4.112.37     0.0%    10   26.2  31.1  23.3  59.3  10.2
  9.|-- 101.4.117.34    10.0%    10   18.8  27.8  18.8  43.9   8.6
 10.|-- 101.4.118.154    0.0%    10   20.6  25.5  20.6  34.4   4.5
 11.|-- 202.97.15.237    0.0%    10   57.1  58.5  43.7  72.2  10.7
 12.|-- 202.97.46.109   60.0%    10   84.3  81.8  73.0  92.3   8.4
 13.|-- 202.97.77.30    60.0%    10  101.2  92.6  84.5 101.2   7.8
 14.|-- ???             100.0    10    0.0   0.0   0.0   0.0   0.0
 15.|-- 220.173.118.215  0.0%    10   97.3  95.9  84.1 105.3   7.9
    1. If a node has 100% loss rate, it probably disallows ping.
    2. Usually, IP nodes beginning with 59.43 represents CN2 line.

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