tag:blogger.com,1999:blog-36470398.post7459954120026293559..comments2023-10-14T10:34:25.304+03:00Comments on Cloud Architecture and Technology Blog: Disk monitoring and tuning with dd and S.M.A.R.T. - Reallocating bad sectors and predicting disk failurecmihaihttp://www.blogger.com/profile/06014247302155057225noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-36470398.post-58904823588004950302008-08-27T13:46:00.000+03:002008-08-27T13:46:00.000+03:00dd (and various variants) basically does a raw cop...dd (and various variants) basically does a raw copy of a target (if) to a destination (of). Variants like dd_rescue attempt to skip blocks that cannot be read or attempt to re-read them, etc. (you can also use conv=noerr to continue copying in case of errors).<BR/><BR/>If you can't mount a file system or there's issue with the partition table, etc. you can still perform a raw disk image (dd if=/dev/disk of=/whatever bs=2048 conv=noerr) or something along those lines.<BR/><BR/>The basic idea is to copy as much data as possible to a disk image, then attempt recovery on that. Tools like dd_rescue will attempt to copy a bad sector multiple times, and disks do automagically remap bad sectors on the fly (if possible). So data recovery is very much possible.<BR/><BR/><BR/>But if you disk isn't recognized by the system at all there's very little you can do (without messing with the hardware).cmihaihttps://www.blogger.com/profile/06014247302155057225noreply@blogger.comtag:blogger.com,1999:blog-36470398.post-17273951520554669542008-08-26T21:25:00.000+03:002008-08-26T21:25:00.000+03:00Impressive knowledge!! I was wondering if you coul...Impressive knowledge!! I was wondering if you could explain something in a bit easier terms. I am trying to understand the dd command or disk utility (if it exists) to recover files from an external hd that does not want to be recognized... <BR/>if this is not the right way to ask... please forgive my ignorance in the matter. thanksdalihttps://www.blogger.com/profile/11740369506279293711noreply@blogger.com