Question: It is sad to say that my external hard drive is currently facing issues.
The hard drive is listed when I run diskutil list (TOSHIBA_EXT):
/dev/disk1#: ??TYPE NAME ??SIZE ?IDENTIFIER0: ?GUID_partition_scheme ??*1.5 TB ?disk11: ??EFI EFI ??209.7 MB ?disk1s12: ??Apple_HFS TOSHIBA EXT ?1.5 TB ?disk1s2
But the hard drive cannot be repair by the GUI Disc Utility, and it cannot be manually mounted with a mount/mount force command because there is a process running on that drive.
I had no idea what this process could’ve been until I saw a massive process (clocking about 45% of my CPU) running called fsck_hfs.
I piped a ps command into a grep searching for hfs (sudo ps ax | grep hfs) :
847 ? ?U ?11:57.49 ?/System/Library/Filesystems/hfs.fs/Contents/Resources/./fsck_hfs -y /dev/disk1s2 999 s000 ?S+ ?0:00.00 grep hfs ?
So my question is: is OS X automatically trying to recover my hard drive for me? Should I just let it the process run it’s course? Why doesn’t OS X tell the user what it’s doing in this instance? Also, what exactly does fsck do?
EDIT: Here’s some more terminal output, this actually seems quite promising:
tail -f /var/log/fsck_hfs.log/dev/rdisk1s2: fsck_hfs started at Mon Dec 14 12:07:40 2015/dev/rdisk1s2: /dev/rdisk1s2: Can’t open /dev/rdisk1s2: Resource busy/dev/rdisk1s2: fsck_hfs completed at Mon Dec 14 12:07:40 2015/dev/rdisk1s2: ** Checking volume bitmap./dev/rdisk1s2: ?Volume bitmap needs minor repair for orphaned blocks/dev/rdisk1s2: ** Checking volume information./dev/rdisk1s2: ?Invalid volume free block count/dev/rdisk1s2: ?(It should be 17331364 instead of 17331357)/dev/rdisk1s2: ** Repairing volume.
So it finished fsck_hfs and is now repairing the volume? Why is this process hidden to the regular user?!
Answer: HUGE PSA for Mac users – if you’re external hard drive isn’t viewable from anywhere besides disc utility, but you see there is activity on your hard drive (i.e – rapid blinking light), let OS X handle it, it is running a recovery daemon.
You can verify this by simply running Activity Monitor (Finder > Go > Utilities), if you see a process called fsck_hfs, and it’s eating up your a good portion of your CPU, this is that recovery daemon!
If you’d like to track the progress of the drive recovery enter this command in Terminal:
tail -f /var/log/fsck_hfs.log ?
tail -f will update the last 10 lines of this log file whenever it updates.