Sharing Engine/Hosting

Currently the transitionnetwork.org site is hosted on a 3GB RAM Debian virtual server in Sheffield and it is documented on the trac wiki. The virtual server is provided by Webarch Co-operative Limited and they are also able to offer fast green virtual servers running in Iceland (where all electricity is from renewables) and co-location in Sheffield.

It is anticipated that traffic to the site will dramatically increase when the Sharing Engine goes live as it will involve embedding pages from the Transition Network site onto other sites using iframes and in order to ensure that the site is responsive under load the migration to faster hardware is being considered.

In Feburary 2012 an aditional 1GB of RAM was added to the live server, (see ticket #397) and it was agreed to consider adding more after a months evaluation of the effect this has. It was further agreed to consider other options later in the year, these other options are documented below.

In addition we are investigating running the site via nginx rather than apache, see ticket #357. Time spent editing this wiki page is being tracked on ticket #392.

Current Hardware

The current virtual live server is running on a physical host with a pair of 2.00GHz dual core Intel Xeon's and the disks the server is on are a pair of mirrored 2TB Western Digital SATA RAID Edition disks.

Following are some stats from the existing virtual server:

cat /proc/cpuinfo | grep bogomips
bogomips        : 3992.77
bogomips        : 3992.77
bogomips        : 3992.77
bogomips        : 3992.77
 
hdparm -tT /dev/xvda2
 
/dev/xvda2:
 Timing cached reads:   1998 MB in  2.00 seconds = 999.00 MB/sec
 Timing buffered disk reads:  92 MB in  3.03 seconds =  30.34 MB/sec

Hardware Upgrade Options

The following options, and no doubt others, will be considered during 2012.

Iceland Virtual Server

If the virtual server were to be moved to Webarchitects green hosting in Iceland, the servers available there are a lot faster, specifically IBM HS22V blade servers with storage access to IBM DS3500 SAN containing 600 GB SAS disks in RAID 10 configuration. Each blade server has 12 intel CPU cores.

Following are some stats from a 10 CPU core 4GB virtual server in Iceland:

cat /proc/cpuinfo | grep bogomips
bogomips        : 5333.44
bogomips        : 5333.44
bogomips        : 5333.44
bogomips        : 5333.44
bogomips        : 5333.44
bogomips        : 5333.44
bogomips        : 5333.44
bogomips        : 5333.44
bogomips        : 5333.44
bogomips        : 5333.44
 
hdparm -tT /dev/vda1
 
/dev/vda1:
 Timing cached reads:   13642 MB in  2.00 seconds = 6835.36 MB/sec
 Timing buffered disk reads: 210 MB in  3.00 seconds =  69.92 MB/sec

Sheffield Dedicated Virtual Server

If the Transition Network were to purchase a dedicated 1U server and this was colocated in Webarchitects Sheffield data centre then this could either be configured with no virtualisation as a dedicated new live server or it could be virtualised and could host multiple virtual machines, the current live and dev virtual servers could be migrated to it and in addition other virtual servers could be created for other tasks (for example hosting word press sites etc).

Buying a dedicated server would entail a capital outlay for the first year but it would offer substiantial hosting cost savings in subsequent years when compared to leasing virtual machines.

Sheffield New Virtual Server

Webarchitects have a new physical server with dual 8 Core AMD Opteron processors and eight 2.5” 10K RPM 300GB SAS Disks:

cat /proc/cpuinfo | grep bogomips
bogomips        : 4000.05
bogomips        : 4000.05
 
hdparm -tT /dev/md2
 
/dev/md2:
 Timing cached reads:   5054 MB in  1.99 seconds = 2534.64 MB/sec
 Timing buffered disk reads: 486 MB in  3.01 seconds = 161.37 MB/sec

Moving the live site to a virtual server on this machine would make it faster and also would allow for the RAM to be dramatically increased as there is lots more available.