I, for one, am extremely interested in the RAID discussion and want it to stay on the list. It might be technically off-topic, but is useful knowledge for anyone comtemplating mass storage of images scanned from, uh, FILMSCANNERS.
There are a lot of threads on this list that I'm not interested in. Rather than being a topic-nazi, I am not too lazy to use the DELETE key. Try it. Lloyd ----- Original Message ----- From: "Stuart Nixon" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, November 13, 2001 10:30 AM Subject: Can we please move the RAID discussion off-list? (was RE: filmscanners: Best solution for HD and images) > Can we PLEASE take this RAID discussion off-list? > > It is not directly related to scanners. And there is enough misinformation > being thrown around here that it is just confusing everyone. > > There is plenty of reference information for RAID systems on the web and > elsewhere; we don't need to clutter the list up with this IMHO. > > If people want reference information on RAID systems, such as the fact > that RAID 0 is indeed less reliable than a single drive or RAID 1 or 5, I > refer > you to information such as: > http://www.pcguide.com/ref/hdd/perf/raid/concepts/relRel-c.html > http://www.usbyte.com/common/raid_systems_3.htm#Extended%20Data%20Availabili > ty > http://204.56.132.222/courses/CIS312J/FAQ/raid-faq.txt > http://www.dansdata.com/raid.htm > http://www.csr.city.ac.uk/people/lorenzo.strigini/A701/A701material/lecture8 > /A701.8.FTnotes_010312A.pdf > http://www.sas.com/partners/directory/sun/wp/raid.txt > > Thanks > > Stuart > > p.s. I saw some Mac users were asking about IDE RAID systems. > Have a look at the new IDE/SCSI RAID 5 boxes from Promise and others, > which have IDE drives, and SCSI out. > http://www.promise.com/Products/UltraTrak/UltraTrak100%20TX4%20&%20TX8%20Dat > a%20Sheet.pdf > A 8 x 100GB IDE drive system gives about 700GB of usable space. I like > these > external RAID boxes, because they are low cost, have hot swappable drives > and power supplies, and plug straight into a Mac/PC/Unix SCSI controller. > > > [Original message] > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Austin Franklin > Sent: Tuesday, 13 November 2001 10:53 PM > To: [EMAIL PROTECTED] > Subject: RE: filmscanners: Best solution for HD and images > > > > MTBF of a RAID-0 system (or dual cpu/memory where one unit CAN > > NOT continue > > without the other) will always be lower than a single drive unless the > > standard deviation (they never quote SD) of the MTBF is zero. > > Well, if you take duty-cycle into account, which MTBF calculations do, you > will actually get higher MTBF for RAID 0, simply because the main failure is > the servo actuator, and when it is only being used for half the time...MTBF > will increase. > > > The reality for MTBF of a RAID-0 will lie in between. > > But that means it doesn't change compared to a single drive... > > > Cummalative failure rate is a much more useful figure for us and > > for a small > > number of fairly reliable inter-dependant devices this is nearly > > an additive > > figure - but not quite. > > That I completely disagree with. It is absolutely NOT additive. In fact, > as I pointed out above, you may get HIGHER reliability by using RAID 0 > simply because of duty cycle and the common failure mode, both of which are > a very important part of MTBF. > > > Seagate reckon about 3.41% (flat-line model) will fail during the first 5 > > years of use (assuming you only use it for 2400 hours a year [6 > > 1/2 hours a > > day]) : > > > > http://www.seagate.com/docs/pdf/newsinfo/disc/drive_reliability.pdf > > If you read that article you referenced, when they talk about multiple > disks, they are talking about multiple PLATTERS in a single disk, not > drives, so you can't derive the numbers you did for multiple drives from > that article. No where in that article did they discuss multiple drives. > > >