In the Beginning
I have been employed in my current role since 2004.
When I started, there was a generic PC running Netware 3.11 Server the files on which were soon transfered over to SBS2003 running on a noname server with IDE disks.
Within a year I had imaged and re-lifed the Small Business Server onto a Dell Poweredge 750 running SCSI disks and then later moved it onto a Poweredge 1950 on SAS disks. Anyone who has done this knows what a challenge it can be to transfer the OS onto dissimilar hardware.
The Results of Non-Virtualized Organic Growth
As the company has grown. I’ve purchased ERP, SCADA, Forms and other physical servers. So even though we are a small shop I have 8 physical servers sitting in racks that are basically idle most of the day. I believe you should use what you pay for, anything else is wasteful (“waste not want not” my Great Depression era grandparents used to say).
A Flirtation with Enterprise Virtualization
One of the servers I have is a Dell Poweredge 2950 with 8GB of RAM. It is on the VMWare Hardware Qualification List. So I installed the free VMWare ESXi 4 product onto it and have been using it to add virtual servers. When you run multiple VM’s on a server you finally start to see your CPU and RAM be used.
Desktop Virtualization Critical to keeping Legacy Control Systems Running on New Hardware
On our site we run Food Manufacturing processes using PC’s for HMI’s (Human Machine Interface) these PC’s run continuously and after 5+ years started to fail. I couldn’t upgrade the control system software they were running so I had to virtualize the Windows XP Pro operating systems and then run the VM as a guest of a new Dell Optiplex Windows 7 workstation.
Virtualization makes transferring an OS to new hardware trivial. So virtualization and it’s convenience has already made in-roads.
Limited Warranties – Darn right they are limited
When you purchase servers they typically come with 3 yrs of warranty, and then after this period you have to re-warrant them. This process becomes more expensive as the servers age. Once a server is 6yrs old you are pretty much paying at least a third of the cost of the original server for one years warranty and at 6yrs of age a server is slower than a wet week. My servers had all gone into extra time warranty wise being 4-7 years old and it would have been a pain in the neck to purchase individual servers and upgrade each one onto the latest OS.
So I decided to purchase a Dell Virtualization setup running VMWare Essentials.
I wish I could say there is some noble reason why I choose Dell. But in the end my reasons are:
- Every time I do a price check between Dell and HP, Dell comes out significantly cheaper
- I have been working in “Dell Shops” since I started in IT. Go with what you know
- In 8 yrs at my current site none of the Dell physical servers I have purchased have suffered cataclysmic failure
Sizing the environment
To get a measure of the requirements for consolidation of servers you need to take several measures.
- Total used diskspace of current physical servers (dictates how big a SAN you need)
- Total Disk Input Outputs per second (IOPS) (dictates disk and SAN connection speed)
- Total memory of physical servers (for example if you have 10 servers currently with 4GB each you need a VMWare host server with at least 44GB RAM)
Fortunately Dell has a utility that you load onto your Windows and Linux servers called ‘dpack’ which takes measures over time and then writes it to an XML file which you send to their enterprise people and they can size a Virtualization environment to suit your needs.
After the dpack process Dell said I could get away with a 1GB Ethernet iSCSI SAN fabric. But knowing that I’m going to have a Business Intelligence environment running on MS SQL with a potential databaes size of 500GB I chose the 10GB iSCSI environment.
For redundancy you need to be able to move your VM’s from one server to another. So you need several physical servers backed onto a SAN. So I’m using a couple of R710’s with 64GB of RAM in each running 10GB cards.
Backup is critical and I still have a tape backup setup so I’m installing a 10GB card onto one of my newer old physical servers and a Symantec VMWare aware backup software. It’s pricey but… you need to be able to recover a full vm or a file inside a VM.
I’m not really wanting to learn as I go with such a critical environment so I’ve also purchased a Dell consultant to “Rack-and-Stack” it. Meaning that they will get me to the VMWare installed and running and a couple of my current servers virtualized before they hand it over.
More to come
I haven’t received the physical hardware as yet so I can’t really blog about the physical implementation until it happens so that will wait till another post.
There are other options
You could of course run your VM’s on one server with a lot of disk and then have a good backup software like Veeam to take solid backups to restore in case of hardware failure but what happens if the single server fails? You would still need another server to fail over to. An Equalogic storage array is pricey at around 20-25K filled with disks but it’s not as pricey as a weeks downtime due to not having a good redundant setup.