On Wednesday 03 March 2010, Mike McCarty wrote: >Don Quixote de la Mancha wrote: >> "Has Your Data Been Saved?" -- Saint $ilicon >> >> Have You Got Religion? If you didn't have Religion before, I bet you do >> now! > >Everyone in foxholes prays :-) > >> Just a week or so ago there was a thread on this list started by >> someone who had a very slow hard drive, that turned out to be failing >> some tests. > >You are probably talking about me. That disc has passed every test >I can give it. It has done the SMART offline collection, short test, >long test, and conveyance test. I have run disc diagnostics which >read every sector. Aside from being slow, it has passed every test >with flying colors, and it has not even one reallocated sector. > >So, I'm still living with an apparently good disc which is unexplainably >slow. > Modern big disks are apparently formatted for 4096 byte blocks while the linux view of a disk is still done with 512 byte blocks. We are being told that if the partitions are not aligned to these 4096 byte fence posts, the drive will be slow because of the on the fly translations. As to the veracity of that claim, I have NDI. However, an F10 original install was obviously slower than the F6 it replaced, then the disk started crying to smartd and I replaced it, partitioning and formatting it the way I wanted, and when the rsync to the new drive was done, and grub fixed, the old F10, on the new drive, was subjectively several times faster. Read into that what you want. >OTOH, I have a recent full backup of all my data. You should invest in another 1Tb disk, set that up so amanda can use v-tapes on that big disk, setup amanda to run every night via an entry in the amanda crontab. End of worries and 100% automatic. >> Your BIOS test is very little more than a basic sanity check. All it >> is really able to do is check whether your disk is working at all. It > >It may read SMART data. Many BIOS do. > >[...] > >> While I know that it's not PC to recommend completely Non-Free >> software, for something like disk drive diagnostics, you really want >> to use the diagnostic tools provided by the vendor of your particular >> hard disk. Every disk drive manufacturer provides these tools as a >> free download from their website. > >This is untrue. I have, for example, a SEAGATE external USB hard disc >for which they do not provide a free download of diagnostic software. I >have complained about this to them, and plan to check back in >a few months to see whether this has changed. > >MOST manufacturers provide such software for all their drives. If >SEAGATE doesn't come up with one, I'm going to be more circumspect >about purchasing their drives in the future. I'll check first for >the diagnostics' existence. > >[...] > >> Generally there is a short test, a non-destructive basic test, a >> non-destructive long test, and a destructive test that writes zeroes >> to every sector of the drive. The short test is the one that will >> access the JTAG functions of all your chips - this test only lasts a >> few seconds. > >Umm, there is an "offline test" which does mostly what you suggest, >but is not really a test, only a data collection, a short test which >actually reads a bunch of sectors, and a long test (extended) which >supoosedly reads every sector. > >WD specifies that on one drive I have their "offline test" takes 8400 >seconds (which is more than two hours), the "short test" takes 2 >minutes, and the "extended test" takes 100 minutes. > >Some drives also support a "conveyance test" which supposedly checks >for likely damage as a result of conveying (physically moving) the >disc. WD specifies that their conveyance test on one drive takes 5 >minutes. > >Also, MAXTOR, for example, specifies that the "offline test" (not >really a test, but a data collection) on one of their discs takes over >four minutes. > >Your information is correct in the essentials, but somewhat incorrect >in some of the details of timing. Those tests are not as quick as >you suggest on the drives I have access to, which are not all that >big. > >> If any of these tests fail, don't wait another minute! Back up your >> drive *completely* and replace it. Your data is worth far, far more >> than any amount of money that you paid for your laptop. A brand-new >> 2.5" SATA drive that is a lot bigger than your current drive will only >> set you back a hundred bucks. > >This is undoubtedly the best information that can be given. >Immediately perform a full backup. Then test that backup, to >ensure that data can actually be pulled back from it successfully. >Then, get a new drive, and using whatever technique you like >clone off the data. > >[more very good stuff snipped...] > >> If it turns out that I can't just fixed the problem, I am able to run >> a full backup under SystemRescueCd to the external drive, then either >> reformat and reinstall the failed system, or remove the failed drive >> completely and replace it with a brand new one. > >You reformat and reuse failing drives? Did I read that right? > >> I'm gonna write this all up in a more coherent and detailed way and >> post it on my website: http://www.dulcineatech.com/ I'll post the >> link here when it's online. But probably not until this weekend. > >I'm sure we're all waiting, like the fisher, with baited breath. > >I know I'm interested in reading what you have to say. > >Mike > -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) It's faster horses, Younger women, Older whiskey and More money. -- Tom T. Hall, "The Secret of Life" -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
