I heard that the major source of memory corruption in servers is the memory bus. And this becomes worse as you add memory sticks. With 8 memory stics that have 8 chips in both sides, you has 128 chips. So the main purpose of ECC is correcting bus errors.
2007/11/26, David Mathog <[EMAIL PROTECTED]>: > > I ran a little test over the Thanksgiving holiday to see how common > random errors in nonECC memory are. I used the memtest86+ bit fade test > mode, which writes all 1s, waits 90 minutes, checks the result, then > does the same thing for all 0s. Anyway, this was the best test I could > find for detecting the occasional gamma ray type data loss event. The > result: no errors logged in 5 solid days of testing. So this class of > error (the type ECC would detect and probably fix) apparently occurs > on these machines at a rate of less than 1 per 840 Gigabyte-hours. > Possibly the upper limit is half that if data can only be lost > on 1 -> 0 transition, or vice versa. This assumes the bit fade test > works, which cannot be independently verified from these results. > > On the web there are references to an IBM study which found 1 bit > error/256Mb/Month, which would have been (.25 *30 * 24) = > 1 per 180 Gigabyte-hours. If IBM's numbers held for my hardware > there should have seen 4 or 5 errors in total. Mine are in a basement > in a concrete building, perhaps that provided some shielding relative to > what IBM used for their test conditions. > > The memory was Corsair Twinx1024-3200C2. When first installed all > of this memory had run for 24 hours with no errors in normal > memtest86+ testing. > > Regards, > > David Mathog > [EMAIL PROTECTED] > Manager, Sequence Analysis Facility, Biology Division, Caltech > _______________________________________________ > Beowulf mailing list, Beowulf@beowulf.org > To change your subscription (digest mode or unsubscribe) visit > http://www.beowulf.org/mailman/listinfo/beowulf >
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