A number >1 is 1 too many



My hard drive on my Mac was acting a little strange lately. More specifically I was getting spinners and sometimes beachballs when I tried to open a folder. This hard drive is the Users storage area for all the accounts on this Mac so I can’ afford to have it fail. Through a lot of careful planning I was able to create a new RAID1 disk on the Mac from the old RAID disks recovered from the Ubuntu servers (a topic I’ll cover in another post). SmartReporter displayed nothing and Disk Utility still had the hard drive’s SMART status as verified. Being cautious about the last “verified” hard drive that is sitting in a drawer waiting for me to save enough to take it to a recovery service I decided to be a bit more proactive and get the actual SMART results. Using SmartReporter again, I had it read out the SMART attributes and this is what I saw.Screen Shot 2012-12-16 at 6.49.30 PMFor hard drives you need to pay attention of a few things: Reallocated Sector Count, Current Pending Sector Count, and Offline Uncorrectable. The first will tell you that the media is failing so be cautious; you can continue to use the hard drive but it will fail, soon. The second will tell you if data is being copied from that failed sector to another currently (flashing yellow lights). The third is saying it’s already too late, you are losing data as we speak. The first 2 are critical, the last can make backups a nightmare because the OS will try to read a bad sector, fail, and stop any operation including backups in progress.

Knowing what was going down I immediately started an rsync
sh# sudo rsync -av /Volumes/Data/Users /Volumes/RAID\ Drive/

What proceeded was hours of frustration as things got progressively worse. Rsync would start the files would begin to copy and after a few minutes or hours the drive would disconnect. Figuring the drive might be overheating I isolated it from the others and installed another fan directly in front of it to keep cool air moving over it. Every few hours I would have to restart the Mac because the drive would stop responding and the only way to get it back is to reboot. Eventually, I started triaging data, deciding what needed to be copied right away and what could be done later. The wife and kids folder went first, they were smaller and took just a few minutes. My Library, Photos, and Documents folder was my priority; Dropbox was safe since it was in the cloud. My music folder was backed by iTunes Match (which expired a few days later) and Videos folder was the lowest.

After many hours (a day I would say) I was finally able to transfer the entire volume onto a RAID-backed array. With everything back where it belongs I relinked the Users folder and all is right in the world. I was planning to copy the data to this drive so I could format the SSD into a Fusion Drive. For now, it will have to wait while I create a new strategy to backup, format and restore to the SSD.