Hi bob, > One half of the RAID array looks dead and the other riddled with > bad blocks including some of the main support librarys.
Was (is) there a regular scrub happening on the array, e.g. `mdadm --action=check'? I think some distros have a cron job that does this regularly for all of md(4)'s arrays. https://en.wikipedia.org/wiki/S.M.A.R.T.#Accuracy has some interesting stats from a, now old, Google summary of its large pile of rust. A field study at Google covering over 100,000 consumer-grade drives from December 2005 to August 2006 found correlations between certain S.M.A.R.T. information and actual failure rates: In the 60 days following the first uncorrectable error on a drive (S.M.A.R.T. attribute 0xC6 or 198) detected as a result of an offline scan, the drive was, on average, 39 times more likely to fail than a similar drive for which no such error occurred. First errors in reallocations, offline reallocations (S.M.A.R.T. attributes 0xC4 and 0x05 or 196 and 5) and probational counts (S.M.A.R.T. attribute 0xC5 or 197) were also strongly correlated to higher probabilities of failure. Conversely, little correlation was found for increased temperature and no correlation for usage level. However, the research showed that a large proportion (56%) of the failed drives failed without recording any count in the "four strong S.M.A.R.T. warnings" identified as scan errors, reallocation count, offline reallocation and probational count. Further, 36% of failed drives did so without recording any S.M.A.R.T. error at all, except the temperature, meaning that S.M.A.R.T. data alone was of limited usefulness in anticipating failures. Cheers, Ralph. -- Next meeting: Bournemouth, Tuesday, 2018-09-04 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread: mailto:dorset@mailman.lug.org.uk / CHECK IF YOU'RE REPLYING Reporting bugs well: http://goo.gl/4Xue / TO THE LIST OR THE AUTHOR
