dave@onfcanim.UUCP (Dave Martindale) (08/26/87)
Are all small hard disks unreliable compared with good large ones? The context: We have a VAX with a few Fujitsu Eagles on it. The specified MTBF for these drives is 40000 hours (about 4.5 years), and I'm willing to believe that because, other than one HDA that suffered from infant mortality, they have been running for more than 2 years, 24 hours a day, without a single failure. On the other hand, we have a few workstations with Vertex 70 Mb hard disks (5 1/4 inch full height) that seems to have a MTBF of something under 1 year. The major problem seems to be drive bearings that get too stiff for the motor to turn. Now, is this just a bad example, or are there 5 1/4 inch disks that do have MTBF's in the range of several years when run 24 hours a day?
hartzell@boulder.Colorado.EDU (George Hartzell) (08/27/87)
In article <15376@onfcanim.UUCP> dave@onfcanim.UUCP (Dave Martindale) writes: >Are all small hard disks unreliable compared with good large ones? > >On the other hand, we have a few workstations with Vertex 70 Mb hard >disks (5 1/4 inch full height) that seems to have a MTBF of something >under 1 year. The major problem seems to be drive bearings that get >too stiff for the motor to turn. We have gone through several Vertexes (Vertexi?) on our Silicon Graphics 2400 within 2 years. We switched to a 5.25 Hitachi (don't know the model) and have had no disk related problems (we now have a pair in the machine). g. George Hartzell (303) 492-4535 MCD Biology, University of Colorado-Boulder, Boulder, CO 80309 hartzell@Boulder.Colorado.EDU ..!{hao,nbires}!boulder!hartzell
roy@phri.UUCP (Roy Smith) (08/28/87)
In article <15376@onfcanim.UUCP> dave@onfcanim.UUCP (Dave Martindale) writes: > We have a VAX with a few Fujitsu Eagles on it. The specified MTBF for > these drives is 40000 hours (about 4.5 years) [...] On the other hand, > we have a few workstations with Vertex 70 Mb hard disks (5 1/4 inch full > height) that seems to have a MTBF of something under 1 year. First off, Fuji Eagles (2351's) are (at least as far as I'm concerned) the yardstick by which disk drive reliability is measured. Their service record is famous in the industry. Not all big disks do so well, any many do far worse. Consider, for example, the DEC RA-81. We've had an RA-81 for about three years. We're on our third HDA, which was recently reformatted because of too many soft errors, and it looks like this HDA is going to be replaced soon. Other RA-81 owners will tell you similar tales of woe. Second, your Eagles are probably running in an air-conditioned clean environment and your Vertex's are probably in somebody's office and thus subject to considerably more environmental strain. -- Roy Smith, {allegra,cmcl2,philabs}!phri!roy System Administrator, Public Health Research Institute 455 First Avenue, New York, NY 10016
dave@westmark.UUCP (Dave Levenson) (08/29/87)
In article <15376@onfcanim.UUCP>, dave@onfcanim.UUCP writes: > ...Are all small hard disks unreliable compared with good large ones? While some brands of "small disks" seem to have shorter MTBF than others, I believe that small disks, as a class, are no less reliable than large disks. The difference, however, is that small disks tend to be installed in small machines. Small machines tend to sit on desks or workbenches, in dusty or smokey or mechanically-noisey environments. They tend to be powered up and down a lot. They tend to be moved around while powered up. They tend to be in over-heated (actually, under-cooled) rooms. Collectively, all of these factors reduce the actual TBF of disks and other things that move. -- Dave Levenson Westmark, Inc. A node for news. Warren, NJ USA {rutgers | clyde | mtune | ihnp4}!westmark!dave
apn@nonvon.UUCP (apn) (08/30/87)
In article <15376@onfcanim.UUCP> dave@onfcanim.UUCP (Dave Martindale) writes: >Are all small hard disks unreliable compared with good large ones? > >The context: We have a VAX with a few Fujitsu Eagles on it. The specified >MTBF for these drives is 40000 hours (about 4.5 years), and I'm willing to >believe that because, other than one HDA that suffered from infant mortality, >they have been running for more than 2 years, 24 hours a day, without a >single failure. > >On the other hand, we have a few workstations with Vertex 70 Mb hard >disks (5 1/4 inch full height) that seems to have a MTBF of something >under 1 year. The major problem seems to be drive bearings that get >too stiff for the motor to turn. > >Now, is this just a bad example, or are there 5 1/4 inch disks that do have >MTBF's in the range of several years when run 24 hours a day? Well.... In general you get what you pay for... most drives fall in to the consumer "trash" category, in my opinion. The only reliable ones I have seen out of about 15 or so brands I used are Fuji, CDC, and Maxtor.. in *that* order. and, yes... fuji does make a st506 interface drive... that would fit the same place as the Vertex you have [ V185 is it ? ] -alex p novickis -- UUCP: {ihnp4,ames,qantel,sun,amdahl,lll-crg,pyramid}!ptsfa!nonvon!apn {* Only those who attempt the absurd ... will achieve the impossible *} {* I think... I think it's in my basement... Let me go upstairs and check. *} {* -escher *}
aburt@isis.UUCP (08/31/87)
An ad from a place called Priority One Electronics that was mailed along with
the most recent Byte had a table giving disk statistics for a variety of
disks; including MTBF. I tossed the ad, but I recall most drives were
15,000 - 20,000 hours. The only specific number I remember was 20,000 for the
Seagate ST-251 (because that's what I have).
I recall that the numbers I knew were indeed correct on the chart (such as
access speed, unformatted size, number of cylinders) but they didn't cite
their sources.
--
Andrew Burt isis!aburt
Fight Denver's pollution: Don't Breathe and Drive.jfh@killer.UUCP (09/02/87)
In article <2025@sigi.Colorado.EDU>, hartzell@boulder.Colorado.EDU (George Hartzell) writes: > In article <15376@onfcanim.UUCP> dave@onfcanim.UUCP (Dave Martindale) writes: > >Are all small hard disks unreliable compared with good large ones? > > We have gone through several Vertexes (Vertexi?) on our Silicon Graphics > 2400 within 2 years. We switched to a 5.25 Hitachi (don't know the model) > and have had no disk related problems (we now have a pair in the machine). Needless to say, the summary line is selfevident. Anyhow, I have seen different manufacturers disk go anyplace from 6 months to 3 years. (The three year version wound up being sold for scrap because it wasn't PC compatible) All of these machines were subjected to the same treatment - leave them on 24 hours a day. The best luck I've had was with a Radio Shack. That's the one that lasted three years without a failure. The one time it died was because of a failed power supply in the drive. The worst was I believe a 40 MB Rodime. The bushings on the ends of the spindle wore out which made the disk as noisy as can be. - John. -- John F. Haugh II HECI Exploration Co. Inc. UUCP: ...!ihnp4!killer!jfh 11910 Greenville Ave, Suite 600 "Don't Have an Oil Well?" Dallas, TX. 75243 " ... Then Buy One!" (214) 231-0993