Instead of writing new articles, I recently spent a lot of time fighting laptop hard disks going bad.
The first was a Seagate ST1000LM14 (apparently originally a Samsung design), a hybrid 1TB 5,400rpm disk with 8GB flash. The disk was installed in a Lenovo Z50-75 laptop and started failing after only about 7 or 8 months. The interesting thing is that the disk didn’t have bad sectors but rather CRC errors on the SATA interface during transfers.
The disk was set up for dual booting with Windows and Linux, each using close to 500GB. Linux (Ubuntu 14.04) could somewhat deal with the transfer errors by reducing the SATA transfer speed and retrying very hard. Windows 8.1 on the other hand wouldn’t even boot, couldn’t repair itself, and entirely failed to produce any kind of useful diagnostic. Boo.
After attaching the disk to a USB adapter, I was able to move the recovery partition off of it without problems, used the recovery partition to reinstall Windows on a new disk, and then copied the nearly 500GB Linux partition again without any problem whatsoever.
I have no idea what happened to this disk. It appears like a problem with failing electronics rather than bad media. The drive was replaced by a newer model, a Seagate ST1000LM15. Time will tell if that was a good idea.
Bad Apple #2
Only about three weeks later, my MacBook Pro refused to boot after being turned off for about a week. OS X would start booting and then the laptop simply turned itself off without indicating why. Boo again. This is a 2012 MacBook Pro with Apple-shipped 750GB 7,200rpm disk. The disk appears to be a Hitachi/HGST Travelstar 7K750.
Further probing revealed that the main HFS+ partition was in an inconsistent state and the root filesystem could not be mounted, which is what caused the machine to turn itself off.
The recovery partition could still be booted without a hitch, and the filesystem could be mounted in read-only mode. I immediately proceeded to copy everything off to an external disk. Copying about 700GB of data hit two bad sectors in unimportant Firefox cache files but otherwise went smoothly.
All attempts to repair the filesystem utterly failed. It appears that Disk Utility/fsck was stymied by a dreaded “I/O error”. Rebuilding the catalog multiple times made most of the files in the main partition vanish but failed to bring the filesystem to a usable state, even when no I/O errors were occurring.
So I zapped the partition and copied back the previously saved files. This went smoothly and after copying the 700GB back, the system is booting again. The disk is scheduled to be replaced with a Travelstar 7K1000, the only 7,200rpm large laptop drive I could find.
Again I have no idea what really happened. The system was shut down cleanly but a week later refused to boot up even once. It looks like a bad sector possibly developed in some critical area of the filesystem and completely tripped up the HFS fsck. Erasing the partition and rewriting all data probably gave the disk a chance to relocate any bad sectors. The disk seems to be fairly healthy overall and it looks like really bad luck that it stopped booting.
If only SSDs never failed… but alas, that is not the case. And from what I gather, SSDs tend to fail hard, while neither of my bad disks actually resulted in a data loss.