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sansinst_res.GIF (4722 bytes) Global Incident Analysis Center
- Special Notice -
1999 - 2000 SANS Institute
Y2K Power-downs

Is it possible that powering down your system for Y2K will put it in danger, cause it to fail? Several operations centers that run 24 by 7 have warned us that this may be a significant risk. Here is the latest, and best written such advisory.

On the issue of Y2K power-downs:
Since I work for a major disk drive company and have about 15 years experience in both the engineering and manufacturing sides of the business I will speak from what I know.

There are going to be a percentage of disk drives that will fail to come back up after an extended power-down if they have been running for 24/7 over an extended period. The keyword here is "extended"...

When a disk drive has been running 24/7 for an extended period, the slider (the tiny, ceramic air bearing that flies over the disk) will accumulate some amount of 'grunge' (composed mainly of lubrication by-products and media particulates). The amount varies from drive to drive and newer drives will be in better shape generally.

When the disk drive is powered down, the slider is 'landed' in a specially designed area at the inner part of the disk known as the Landing Zone. This landing zone is textured (it has a specially prepared surface roughness) that tends to scrape the 'grunge' off of the slider. It also helps keep the slider from sticking to the
disk (the much dreaded "stiction" problem).

Here are some rules to preserve your data by:

  1. If at all possible, backup and spin-down (this may not require the removal of drive power) the disk drive at least once monthly to keep the accumulation of 'grunge' to a minimum. DO NOT EVER NEGLECT TO BACKUP YOUR DATA. PERIOD. YOU HAVE BEEN WARNED.
  2. If you've been unaware of the above or unable to perform this prior to your planned Y2K power-down, then proceed as follows:
    1. Backup your data
    2. Perform a 'short period' power-down, letting the system set for maximum of 30 seconds before powering it back up
    3. Run Non-destructive storage testing on the disk drive
    4. Perform your 'Real' power-down

The intent of a 'short period' power-down is to give the disk drive an abbreviated 'touch-down' of the slider to the landing zone. This will clean some of the 'grunge' while not letting the two set there long enough to get "cozy" (lest the dreaded stiction occur). The storage testing is intended to re-verify the integrity of the drive and give it the opportunity to auto-reallocate any media defects that may have appeared due to the 'grunge' that got scraped loose from the slider and is now floating around inside the containment.

It is unfortunate that people tend to forget that these are precision electro-MECHANICAL devices that have moving parts. They require a certain amount of care and due diligence for them to outlive their usefulness. Properly cared for, a modern disk drive will easily last five years or more. Neglected, a modern disk drive will eat your data and make you crazy.

Which would you choose?

- Greg Houlette

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