11 December 2007 : Virtualisation
The theme of this Forum was Virtualisation. James Tansley gave a very stimulating and informative address on the reasons and technology behind Hamilton Architects' move to VMware Server ESX/Infrastructure 3 and their use of NetApp storage technology. As Wilkinson Eyre are intending to move to VMware Server/ Infrastructure soon, a lot of answers were sought and given.
Hamiltons' move to VMware and NetApp
James gave an excellent description of how his interest in VMware was piqued at a VMware coffee morning where the capability of VMware Infrastructure was displayed by moving a running OS instance streaming video from one physical server to another without dropping a frame of video.
James' preliminary research enabled Hamiltons to make the move to consolidate most of their server infrastructure onto 3 physical VMware ESX hosts, altogether running 16 virtual OS instances in a VMware Infrastructure 3 environment. Three number HP DL380 servers are in service, each with dual Xeon processors, 6 network adapters and 12GB of RAM, each working as minimal VMware ESX hosts on which multiple guest VMware instances can be run. Storage at present consists of 4TB of HP storage accessed over HBA, and around 7TB of NetApp storage, which will shortly be expanded to provide more replication and snapshot facilities.
Virtualising operating systems are being supported by a rollout of NetApp storage devices, which allow flexible apportionment of storage through many interfaces and protocols such as native CIFS and by LUN, while also providing tremendous flexibility in the apportionment of storage. NetApp also has the ability to snapshot filesystems (as discussed at our previous forum) to provide frequent filesystem snapshots which require little additional storage space.
VMware Infrastructure provides the ability to load balance and configure HA (High Availability) operations between ESX hosts. It also permits the management ESX Servers and all virtual machines through a common interface capable of defining topology maps, centralising licensing, monitoring systems and performance and extracting reports.
James said "It now takes minutes to provision a new server, based on a known good VMware instance." He added, "You can set VMware to automatically move resource-intensive applications to the ESX host most suited to serving it" -- VMware's per-virtual-machine MAC address virtual network adapter ensures that such a move is seamless.
James covered many other areas in his stimulating and persuasive talk, including:
- The difference between VMware GSX (VMware running itself as an application on a host OS) and VMware ESX (VMware running its own stripped down host OS).
- The advice not to mix AMD and Intel-based processors in the same Infrastructure environment.
- The necessity of having application-aware snapshot procedures, as VMware snapshots themselves may be useful for restoring an OS to a known state, but database-reliant programmes (including Exchange) require that the application is frozen in a known state before a useful snapshot can be taken for backup purposes. The use of the NetApp snapmanage and snapdrive programmes is essential. James did not consider VMware snapshots a replacement for backup to tape.
- Plans for IBM and HP to provide VMware ESX as a BIOS boot option.
- Craig Barrett, ORMS
- Richard Priest, FCB Studios (formerly Fielden Clegg Bradley)
- Chris Poulton, Hugh Fernando Wilkinson Eyre Architects
- Andy Sheldon, Urban Initiatives
- Rory Campbell-Lange, Campbell-Lange Workshop