disk flaws, classic vs. modern

Message: 19 Date: Sun, 07 Oct 2012 03:51:12 -0600 From: Eric Smith <eric at brouhaha.com> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Subject: Re: disk flaws, classic vs. modern Message-ID: <50715090.2020207 at brouhaha.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed On 10/07/2012 01:38 AM, jim s wrote: When you have a drive go bad in a RAID 5, it's best to pull the drive, put a new one in its place, and start a rebuild. That's the point of using RAID 5. Trying to recover data from the failing drive is mostly a waste of time. Of course, if the drive wasn't in a RAID 5, mirror, etc., you wouldn't have that option. My experience is that once it starts it just gets worse, especially with the newer drives (>100 or so GB) - junk the drive and put a new one in. In fact, based on what I've seen and heard I'd replace more of the drives once you get the bad drive replaced and the array rebuilt, especially if the drives are from the same batch. Marginal drives can and do go out during rebuilds. Of course, if the data on the array isn't critical then this becomes much more flexible- but if it is then you don't want to have your second drive go at some point in the near future, then the third give up while you're attempting to rebuild the array after the second disk's failure. Any reason you're recovering data from the drive rather than rebuilding? I'd go along with Eric here - if you rebuild then you're starting with a known-good array, rather than potentially having errors in your replacement drive. This isn't just anecdotes, either - I've seen numbers. That's one reason I've gone to mirrors on my few critical installations.