iMac 17,1 48GB
3.1 TB FUSION drive (3TB HDD + 128GBSSD)
The Volume Rebuild tool on TTP 10.0.1 wrecked my fusion drive by messing up some metadata in the logical volume group header having to do with the size.
I usually use DiskWarrior 5.1 to compress the directory/B-Tree etc. This time I decided to try Techtool Pro 10 volume rebuild. This happened June 25, 2018 at about 10:30 PM PDT.
I was booted off my e-drive, which is an external SSD. I experimented with the Techtool Pro Volume Rebuild on an unimportant USB HDD. It worked fine...went through all of its steps in the log and then said "No Errors Found". I fsck'd the rebuilt drive and all was well.
Thinking that it worked, I decided to use TTP volume rebuild on my Fusion Drive (which, recall, i was not booted from), which is also my system drive. It looked like it was working, going through the steps up until Recheck. Then it suddenly quit, with a "Recheck Failed" message with no further explanation.
When I tried Disk Warrior 5.1, I got an apple "the disk you have attached is not formatted" error dialog when I tried to rebuild my system drive. I clicked "ignore" and continued. Disk Warrior 5.1 hung for 40 minutes in step 8. Disk Warrior 5.1 is read-only until the very last step 10, which it never reached, so it didn't screw anything up.
I ran Apple Disk Utility on my system drive (still booted from e-drive). Disk Utility hung permanently during an fsck.
I force-quit Disk Utility, powered the machine down by force with the power button, and tried to reboot into the system disk recovery portion using command-R (or whatever it is). What I got instead was apparently a clean boot into my normal system drive; not the recovery partition, not the e-drive (and yes I was holding down the right keys). Apple disk utility showed the fusion drive as NOT split...it was still all one volume.
I tried to do a live First Aid on my system drive using Apple Disk Utility. This worked, and solved the problem. The error that it reported in its log, which I unfortunately didn't keep to append here, basically said that the size of the logical volume group for the fusion drive only included the HDD, not the SSD. The last two lines of the Disk Utility fsck log were something like "restoring size of logical volume to 311,xxx,xxx,xxx" and "expanding partition". The operation concluded with "success" and the system drive is now working normally. I booted back to the the e-drive and used Disk Utility and Disk warrior on my system drive when unmounted. Everything worked fine.
In my mind, this raises the possibility that the TTP 10 volume rebuild tool may have a bug that allows it to sometimes screw up the metadata of a fusion drive's logical volume group structure by leaving out the SSD capacity.
3.1 TB FUSION drive (3TB HDD + 128GBSSD)
The Volume Rebuild tool on TTP 10.0.1 wrecked my fusion drive by messing up some metadata in the logical volume group header having to do with the size.
I usually use DiskWarrior 5.1 to compress the directory/B-Tree etc. This time I decided to try Techtool Pro 10 volume rebuild. This happened June 25, 2018 at about 10:30 PM PDT.
I was booted off my e-drive, which is an external SSD. I experimented with the Techtool Pro Volume Rebuild on an unimportant USB HDD. It worked fine...went through all of its steps in the log and then said "No Errors Found". I fsck'd the rebuilt drive and all was well.
Thinking that it worked, I decided to use TTP volume rebuild on my Fusion Drive (which, recall, i was not booted from), which is also my system drive. It looked like it was working, going through the steps up until Recheck. Then it suddenly quit, with a "Recheck Failed" message with no further explanation.
When I tried Disk Warrior 5.1, I got an apple "the disk you have attached is not formatted" error dialog when I tried to rebuild my system drive. I clicked "ignore" and continued. Disk Warrior 5.1 hung for 40 minutes in step 8. Disk Warrior 5.1 is read-only until the very last step 10, which it never reached, so it didn't screw anything up.
I ran Apple Disk Utility on my system drive (still booted from e-drive). Disk Utility hung permanently during an fsck.
I force-quit Disk Utility, powered the machine down by force with the power button, and tried to reboot into the system disk recovery portion using command-R (or whatever it is). What I got instead was apparently a clean boot into my normal system drive; not the recovery partition, not the e-drive (and yes I was holding down the right keys). Apple disk utility showed the fusion drive as NOT split...it was still all one volume.
I tried to do a live First Aid on my system drive using Apple Disk Utility. This worked, and solved the problem. The error that it reported in its log, which I unfortunately didn't keep to append here, basically said that the size of the logical volume group for the fusion drive only included the HDD, not the SSD. The last two lines of the Disk Utility fsck log were something like "restoring size of logical volume to 311,xxx,xxx,xxx" and "expanding partition". The operation concluded with "success" and the system drive is now working normally. I booted back to the the e-drive and used Disk Utility and Disk warrior on my system drive when unmounted. Everything worked fine.
In my mind, this raises the possibility that the TTP 10 volume rebuild tool may have a bug that allows it to sometimes screw up the metadata of a fusion drive's logical volume group structure by leaving out the SSD capacity.
