> -----Original Message----- > From: Max Waterman [mailto:davidmaxwaterman@xxxxxxxxxxxxxx] > Sent: Thursday, December 18, 2008 4:52 PM > To: David Lethe; Justin Piszcz; John Robinson > Cc: Linux RAID > Subject: RE: upgrade advice / Disk drive failure rates - real world > > > On Thu, 18 Dec 2008 13:14:27 -0600, "David Lethe" <david@xxxxxxxxxxxx> > said: > snip > > > > So aggregate walk-away > > - Keep disks in 36-42 degrees C for maximum life up to year 2, where > > they should be run cooler. > > - New disks are 5x more likely to die in first 3 months with high > vs. > > low workload. > > I wonder if you can use this fact to make drive which are more likely > to > fail later, actually fail sooner. > > I'm thinking that I could run my new drives in a fridge for a month or > two or three - if they fail, I'll return them, else I can be more sure > they'll last their expected life and not give me any trouble. > > Does that make any sense? > > Also, I see people recommending enterprise disks, which makes me think > that those same people have forgotten what the 'I' stands for in > 'RAID'. > Of course, 'inexpensive' is relative - probably to one's income and it > seems some people are paid more than others....it almost suggests we > should have another acronym - RADCD - redundant array of dirt cheap > disks. :) > > Max. If it is your desire to fail the drive as quickly as possible, you definitely need that environmental chamber, but more importantly the right software test suite. The big-box RAID vendors spend a lot of money developing stress environments so they weed out the ones that are likely to fail before they ship, and the code they use is a big trade secret because this differentiates the tier-1s (EMC, NetApp, etc..) from everybody else who doesn't have enclosures that can survive a shotgun blast or a drop test. Th It is public knowledge that sudden changes in temperature under high IOPs & seeks is a reasonable part of a test suite. Large block copies isn't stressful. You will want to change some of the programmable drive settings, but won't tell you specifics because I am not at liberty to tell you what any particular vendor does. (But some settings make a lot of sense if you read the ANSI specs and drive vendor's product manuals and you put 2+2 Together). Vibration is good too. Don't use your freezer however, there are better ways to go. For instance, if you were lucky enough to get an Omaha steaks gift package like me yesterday, then you have a 100% Styrofoam chest that is perfect for your needs. You can stick in some dry ice, carve out a hole for a hair dryer to fit into, and put in a fan in the bottom so you can equalize pressure. You will want to create some vibrations. Maybe use a massage pad, or you can easily create enough sonic pressure if you have a teenage daughter with a cell phone. It won't be nearly as good as a tier-1. They just need 48 hours with their equipment to do better than what you can get with a 3 months worth of usage. Still perhaps a week in the Styrofoam ice chest with random small block I/O Will get you close enough. David ��.n��������+%������w��{.n�����{����w��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
