[ale] disk drive lubricant

Mon May 15 15:09:07 EDT 2006

Now that brings back fond memories of Seagate ST-225s & ST-251s
On Mon, 2006-05-15 at 10:32 -0400, Mark Wright wrote:
> I used to work for a mainframe disk manufacturer.  One of the issues  
> that all disk manufacturers face is the lubricant.  one line of disks  
> we produced failed because we were using new (in the 80's) sputtering  
> technology to put the oxide on the platters.  The engineers were so  
> proud of the fact that they could fly the heads at 7 microns because  
> the media surface was so smooth.  The only problem was that after  
> about six months the lubricant would migrate out across the platters  
> and get on the low flying heads.  It would change the aerodynamics of  
> the head and lift it up too high to read the data.
> 
> Any way the point of the story is that lubricant on the media is a  
> known factor in disk design (one the above mentioned engineers over  
> looked).  One of the ways it can bite you is when the drive is  
> powered off the head comes to rest on the platter, the lubricant  
> cools and the head gets stuck.  I have some mid 90's technology  
> controllers that used 100 Meg laptop disks current at the time, to  
> boot from.  They only get booted maybe once a year.  If you power one  
> off for 30 minutes you have a fifty- fifty chance it won't come up.   
> Our fix has been to take the drive out and bang it on a table top  
> pretty hard.  This pops the heads loose and the thing boots.
> 
> If you are going to use hard disks for archival storage  make it  
> battery supported RAID and never power them off.  Then write a script  
> or a program to incrementally read and re-write the data periodically  
> so that every few months you know that all the data on the array is  
> fresh.  (sometimes data written a year ago is hard to read due to  
> mechanical wear like in the unusual story above.)
> 
> I wouldn't worry about the temp or the humidity except to make sure  
> that it is relatively constant.  Drives can handle most anything but  
> change.
> 
> What fun,
> 
> Mark
> 
> 
> 
> 
> On May 14, 2006, at 6:44 PM, Dow Hurst wrote:
> 
> > Greg,
> > Not so urban legend as an DEC engineer told me, about a decade ago,  
> > that
> > a SCSI drive can lock up due to returning to room temperature for too
> > long.  He explained that the normal running state had the disk drives
> > warmed to a normal running temperature.  When a drive wouldn't restart
> > after a machine failure that he had fixed, he would try warming the
> > drive with a hairdryer and then try restarting the server.  I lived in
> > fear of our SGIs being down too long with the drives getting cold!!
> >
> > I am interested in the lubricant vapor pressure used in disk  
> > drives.  If
> > you are correct that lubricant can get deposited on the platter  
> > surfaces
> > and heads during storage, then that is a disk design issue.  There
> > should be white papers from manufacturers on that topic available.  I
> > wonder if humidity, pressure, and temperature changes of the  
> > environment
> > where the drives are stored affect the lubricants?  Should they be
> > stored under nitrogen in a constant humidity environment.  At that
> > point, the durability of tape medium and storage costs should come  
> > into
> > play.
> >
> > I think mirrored RAID 5 servers are a wonderful thing.  My personal
> > dream is to have two separate servers with multiple times the storage
> > capacity of the current amount of data that are mirrored to each other
> > with power protection and in separate locations with fat bandwidth
> > between them.  Then, the wet part of the dream is a third secret  
> > server
> > that only I know about in a hidden location that is the ace in the  
> > hole.
> > Dow
> >
> >
> > Greg Freemyer wrote:
> >> Are you planning to power-down the drives between uses?
> >>
> >> If so, there is NO data or gaurentee on disk drives maintaining data
> >> with power off.
> >>
> >> We do it a lot around here, but we also make a tape backup before we
> >> put the drives on the shelf.  Personally I think data loss starts to
> >> happen in the 1 to 2 year range.  I do know some people pull drives
> >> off the shelf every once and a while just to power them up and give
> >> the grease, etc. a good workout.
> >>
> >> I've even heard a guy one time say there were disk drive preheaters
> >> that could be used to warm a disk drive (and associated grease etc.)
> >> up.  Treat that as urban legend.
> >>
> >> Greg
> >>
> >> On 5/10/06, Allan Metts <ametts2 at mindspring.com> wrote:
> >>
> >>> Hi everyone,
> >>>
> >>> I have several hundred Gigabytes of data that's in my way.  I  
> >>> need to keep it, but I don't need regular access to it.  More  
> >>> data is coming in now that will eventually need the same treatment.
> >>>
> >>> So I'm looking for a good solution for off-line data storage.   
> >>> Here's what I'm looking for:
> >>>
> >>> --*-- Rack-mountable
> >>>
> >>> --*-- Non-proprietary hardware, no special "backup" software
> >>>
> >>> --*-- Supports Linux distributions.  I choose which one.
> >>>
> >>> --*-- Uses readily-available and inexpensive IDE drives.
> >>>
> >>> --*-- Easy to set up and administer.  We have no time to fiddle  
> >>> with this -- I'm thinking 1) mount the drive, 2) copy the files,  
> >>> 3) unmount the drive, 4) remove and replace the drive.  The  
> >>> machine still needs to work when I pop in an unformatted or  
> >>> unrecognized drive.
> >>>
> >>> --*-- Hot-pluggable drives would be nice if it doesn't make  
> >>> things complicated.  I'm willing to power down the machine to  
> >>> swap the drives if need be.
> >>>
> >>>
> >>> I think what I'm looking for is a bare-bones rackable server,  
> >>> with an internal IDE drive to boot Linux, a CD-ROM drive to  
> >>> install Linux, and two removable drive bays that I can dump the  
> >>> data to.
> >>>
> >>> Suggestions?  Recommendations?
> >>>
> >>>
> >>> Best Regards,
> >>>
> >>> Allan Metts, VP -- Technology & Operations
> >>> AirSage, Inc.
> >>> ametts at airsage.com
> >>> (404) 861-3404
> >>>
> >>> _______________________________________________
> >>> Ale mailing list
> >>> Ale at ale.org
> >>> http://www.ale.org/mailman/listinfo/ale
> >>>
> >>>
> >>
> >>
> >> --
> >> Greg Freemyer
> >> The Norcross Group
> >> Forensics for the 21st Century
> >> _______________________________________________
> >> Ale mailing list
> >> Ale at ale.org
> >> http://www.ale.org/mailman/listinfo/ale
> >>
> >>
> >
> > _______________________________________________
> > Ale mailing list
> > Ale at ale.org
> > http://www.ale.org/mailman/listinfo/ale
> 
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://www.ale.org/mailman/listinfo/ale