Why you should VM your Print Servers

It’s quite common to run the file server and the print server on the same box. They don’t tend to compete for resources and are moderately complimentary. The downside is the instability of the spooler service combined with varied drivers leads to more frequent reboots than is ideal. Everyone loves to reboot a large file server.

The problem is that no one wants to dedicate hardware to just printing. or heaven forbid, coexisting with a domain controller Another issue with print servers is DR. Lets assume that last driver you installed for the MD’s “all in one piece of junk” sends the print server into a spin and wipes out all the other Canon printers at the same time. There is no easy rollback. MS does provide a printer backup tool, but it is rarely used and doesn’t always sort out the DLL mess that comes from a conflicting driver.So you resort to DR – but hey, you can’t “just restore” the config to another server easily.  You have to restore the whole box. this means having the same hardware on hand, and a lengthy restore time. You could try your luck and sort out the RAID and MB driver mess to get it working on something else, but personally I hate the pain and excessive wasted time.If you do rebuild to a different server, there is a fair chance you’ll also be re-configuring all the desktops onsite. Getting all the configuration details and drivers right is not much fun. Until Longhorn gets here there if little in the way of centralized printer management that works well. Personally, I prefer to let users add their own printers. The downside is that a change on the server will generally be noticed with a huge influx of helpdesk calls. I still prefer that to the “install 10,000 printers on each machine” solutionAll of this makes you start thinking that a VM might be to your advantage.The two key points are this

1. VM’s are hardware independent – Move them to whatever and wherever you will.
2. VM systems are easy to snapshot – and that’s your backup solution solved.

Print servers fit in the category of things that don’t hold data and don’t change much. This makes traditional tape backup rather unwieldy and snapshots a perfect solution.Configuration Rollback – Snapshot the VM before making the change, takes no time compared to backup. If you have a problem – presto – instant rollback.Hardware Failure – Take weekly base OS snapshots of the paused image and back them up. If you need to restore, simply grab the latest and drop it on anything handy.Print servers are not really user interactive. It’s not uncommon to have to wait for a print job, so dropping them onto a box that has marginal performance is going to have little to no impact on user perceptions. This means you can use any old box as you printer server, and if it dies, move it straight to the next one with minimal outage.Advantages

• Reduced backup time / space.
• Simplified Backup
• Simplified Restore
• Significantly reduced DR time
• Rollback is trivial
• Slow hardware is fine – it is not user interactive
• Older hardware is fine – DR is so simple
• Shared VM hardware is fine
• Never rebuild your print server again – just move it
• Never DR your print server again – snapshot it
• Never reconfigure all your desktops again
• Stability means you can ditch all the printer install scripts

With the budget was maxed out I have run a VM print server with 140+ printers including large format and high speed lasers on an old DL360 PIII 500 w/ 1GB RAM and Mirrored 18GB 10K SCSI disks. It sat on 80% + utilization most of the time, and often flatlined on 100%, but I had NO user issues. I didn’t reboot the base OS ever for performance or stability reasons. When the new budget cam through it rolled onto a decent DL380 in a matter of minutes. I was also surprised to find the spooler seemed to be much more reliable when not running on a file server, so possibly there is conflict for resources after all.The portability and DR side meant I could pretty well forget about the box, it would just work, and if it didn’t, there was no stress and almost no downtime.In comparison to a few clustered Print servers I had worked with I found the VM solution to be far more reliable and caused less stress.