So last post, I gave an introduction to virtualization and left off with a small teaser saying that I would discuss my preferred method of deployment. I call this architecture 3DV which stands for 3PAR, Dell and VMWare. I'm fairly certain that anyone reading this article is familiar with Dell and is aware that Dell provides a full line of business hardware. VMWare is somewhat less ubiquitous than Dell, but they provide what I believe to be the best virtualization software to date in the form of their VI3 (Virtual Infrastructure 3) line. Least known of the three is probably 3PAR which provides an excellent line of innovative storage area network (SAN) hardware and software. The combination of these three provides a solid high-performance virtual infrastructure which is flexible on various levels.
This post will cover 3PAR. The backbone of any large infrastructure is storage. Storage needs often grow faster than computing power needs, and sharing storage is key in today's tightly integrated IT environments. There are many SAN vendors out there like EMC and NetApp, but 3PAR differs from these in two key areas - thin provisioning and dynamic optimization. By nature, most SANs force you to allocate all storage space needed by a server at the time you provision it. This means that even though your server may only use 100 GB currently, if you expect the need to grow to 500 GB at any point in the future, you need to allocate 500 GB immediately. Naturally, this leaves about 400 GB of storage space allocated but not used. This is a waste of that space. Multiply this schema across several to many servers, and you can see that a lot of space gets wasted. This practice of allocating more storage than currently necessary is called over provisioning. 3PAR addresses this issue with a technology called thin provisioning. Conceptually, the 3PAR unit presents a logical unit (LUN) to the server of any size you specify, but only fills up the space that is necessary at that point in time on the actual SAN. This means that the server may see a storage space of 1 TB, but the 3PAR is only utilizing 100 GB. The other 900 GB that would otherwise have been immediately allocated to a server and removed from the available storage of the SAN are not actually removed from the available storage pool. They are still available to be used as necessary by the SAN. With this type of provisioning, system administrators can 'thin provision' storage space out to servers up to the physical limit of the SAN, yet not actually have purchased and installed all of the disks that make up that limit in the SAN itself. The system administrator must monitor the actual usage on the SAN and purchase and install more disks as needed. Thin provisioning greatly reduces unused but already purchased and installed storage space on a SAN allowing IT departments to squeeze the most bang for the buck out of their SAN infrastructure. Dynamic optimization conceptually spreads all data on the SAN over as many disks as possible to increase the throughput of data from multiple disks (spindles) and thus increase IOP performance. Thin provisioning and dynamic optimization give the best performance and least cost in a SAN infrastructure.
It goes without saying that 3PAR provides the usual array of SAN goodies like robust connectivity options including iSCSI and Fiber Channel. 3PAR also provides a command line interface (CLI) and an easy to use web-based graphical user interface (GUI.) There are multiple units available for medium to large enterprises and many software tools to enhance the capabilities of the SAN. You can find more information about 3PAR at http://www.3par.com