Should You Leave Your Computers on at Night?

Should you leave your computers on at night or shut them off when you go home?

The answer is "it depends".

There are many factors that go into this decision.  However,  you may be wasting significant amounts of money by not properly evaluating and appropriately managing this issue.  With proper planning and intelligent management CSI can help you maximize productivity, security, stability and find financial savings you may not have even realized you had available to you.  Here are some thoughts to consider:

Reasons to leave your computer on:

1. Windows Updates.   Microsoft by default sets Windows Updates to run at 3am.  Their objective it to apply the updates in the middle of the night to minimize most of the impact to users.   Microsoft generally releases updates on "Patch Tuesday".  The second Tuesday of each month is considered the "major" update day.  This means that machines configured for automatic update will start doing updates on Wednesday morning at 3am.   The fourth Tuesday of each month is the "minor" or "cleanup" update day.   These are generally other updates which may not be critical in nature.   Again the following Wednesday at 3am machines configured to automatically accept those updates will start updating.  Microsoft from time to time releases emergency updates generally to deal with machine security threats.  They could come out any time.  If you are running automatic updates, you could leave your computers on leaving the office on the second and fourth Tuesday of the month and get most major updates.  Then leave them on if you hear about a major security update that happens at other times.   This would minimize the computers being on and consuming electricity and minimizing the impact to users of machines doing updates versus their normal work.  If you manage your Windows Update process via a Microsoft Windows Services Update Server (WSUS), then you can adapt your schedule to whatever your internal testing and deployment strategy is for Windows Updates.
2. Remote Support.  If you have remote maintenance and monitoring process such as Symantec's Altiris, Novell's ZENworks, or Microsoft System Center Configuration Manager, then you may be doing more than just Windows Updates.   You may be remotely deploying applications and updates.   Again doing this when the users are not there is always desirable to minimize end-user productivity.
3. Anti-Virus Updates and Scans.   Many users complain about both network and workstation performance issues during major anti-virus/anti-malware updates.   Some products create something nicknamed "AV Storms" where the act of updating to keep your machines safe from viruses and trojans and spybots can impede the actual use of the computers!   We try to avoid those type of products, but we are not immune to hear user's grumble about bad performance.   Conceptually anti-virus programs have two elements.  First they are pro-active in that they do real-time scans about what is being saved, opened, downloaded, etc. evaluating these files against anti-virus signatures.   These signatures are downloaded automatically either hourly or daily.   However, the second, very important part of anti-virus scanning is to periodically re-scan all your files using the most current anti-virus signatures to find anything that may have slipped into your system before your anti-virus program knew it was a virus.  These "scheduled" scans are very important.  They are also very lengthy and resource intensive (no matter what configuration options the vendor supplies).  If a scheduled scan is running when the user is on, it is hard for them not to notice that their computer is slow.  Running these scheduled scans at night adds this second level of anti-virus protection and eliminates or at least dramatically reduces the issue of users being impacted by  your pro-active security procedures.
4. Remote Access.  I often reach into my computer from home or remotely to do real work.  My computer has access to files and applications that I cannot directly see at home.   If I am sitting by the pool at my daughter's swim practice on my Verizon 3G wireless card, my performance is okay for web and email, but lousy for pretty much anything else.   If I securely remote into the office, I can get much better performance and be much more productive (and less frustrated).  However, to remote into the office, I need a computer that is on and available to accept my remote access request.  While there are many strategies to have computers available to do this, the simplest for me (and for most people) is to just remote into my actual desktop computer.  I am thus sitting at swim practice or at my kitchen and sitting at my desk at the same time.
5. Scheduled Maintenance.  Windows computers sometimes need more than just updates.  Often the performance of the computers can improve significantly by performing simple scheduled maintenance such as defragmenting the disk drives to keep them in an optimal state and deleting/cleaning up temporary files to ensure that there is adequate space. These processes can be lengthy and resource intensive.   Running these processes as a scheduled task at night allows you to balance the needs of the users and keeping the computer running in an optimal state.

Leaving computers on cost money:

The reality is that leaving computers on costs you money.  If you have lots of computers, it costs you  lots of money.  While I have laid out some good reasons to leave your computers on,  most of those reasons require the computers to be on at specific times and days.  The rest of the time they computers don't need to be on.   There are a number of strategies you can employ to balance the needs of leaving computers on versus off to maximize security and productivity and minimize electric costs.

1. Sleep Mode.   Every manufacturer of desktops and laptops has a sleep mode under power management.  This allows the computer to be on, but in a reduced power state.  It is a balance between being off and being left on in terms of power management.   Power management schemes can tell the computers to enter a reduced power state if going through a period of inactivity that you define.
2. Wake on LAN.   This is a feature of most computers.  The concept is that we use something called a "magic packet" to call out the network adapter address of the computer twelve times in a row.  That network adapter remains on even if the computer is actually turned off.   If the network adapter hears it address that many times, it electronically presses the power button to turn the computer completely on.   Once the computer is turned on it can do all the tasks we require it to do.  Once it is done it can shut itself back off to save electricity.  If you turn your computer(s) off via a power strip, then there is no power available to the network card and Wake on LAN cannot work.
3. Intel vPro. This is Wake on LAN on steroids.  Many computers now come with technology built-in.  It is more reliable than Wake on LAN in terms turning on and off.   It allows all sorts of remote support options to help resolve most computer operating system and application issues short of the computer simply will not turn on.  With Intel vPro we can even remotely reload the computer from scratch!  If you turn your computer(s) off via a power strip, then there is no power available to the network card and Intel vPro technology cannot work after hours.