For a while now I have been aware of an occasional stutter in play back and thought the most likely explanation was that hard drive was starting to fail (1TB drive in HDR-FOX T2 purchased December 2010). I installed the custom firmware and started monitoring the reallocated sector count in late May when it was 1106. For the next 8 weeks it was increasing at a rate of about 4 sectors a day reaching 1355 on the 25th July. Since then the rate has increased dramatically and the play back problems have become much more obvious and today the count stands at 1743. I have had a new 2TB Seagate 2TB drive (ST2000VM003) waiting for a few weeks and made the replacement this afternoon. I used the excellent aft123 instructions at http://wiki.hummy.tv/wiki/2TB_Disk_Installation_Blog and the physical replacement was very straight forward taking less than half an hour to remove the old drive and install the new drive. I used the partitioning and file system creation instructions in the af123 article and they worked exactly as described. I then connected the old drive to a USB to SATA converter and then had to think as af123's instructions stop at that point. My method for copying content from the old drive to the new was as follows:
cd /tmp
mkdir mynew
mkdir myold
#Mount new drive partition 1 temporarily on /tmp/mynew
mount -t ext3 /dev/sda1 mynew
#Mount old drive partition 1 temporarily on /tmp/myold
mount -t ext3 /dev/sdb1 myold
#Copy data across; very quick for EPG partition (less than 10 seconds)
cp -afv myold/* mynew
umount myold
umount mynew
#Mount new drive partition 2 temporarily on /tmp/mynew
mount -t ext3 /dev/sda2 mynew
#Mount old drive partition 2 temporarily on /tmp/myold
mount -t ext3 /dev/sdb2 myold
#Copy data across; time will depend on volume of data; 560MB took a bit over 10 hours to transfer
cp -afv myold/* mynew
umount myold
umount mynew
#Mount new drive partition 3 temporarily on /tmp/mynew
mount -t ext3 /dev/sda3 mynew
#Mount old drive partition 1 temporarily on /tmp/myold
mount -t ext3 /dev/sdb3 myold
#Copy data across; took 40 seconds.
cp -afv myold/* mynew
umount myold
umount mynew
Put the HDR into standby and then restart.
Based on a single data point and our tolerance to stutter in playback, I would suggest a tentative initial conclusion that a 1TB hard drive with less than 1000 reallocated sectors is usable (I guess this would suggest 500 sectors as a tolerance for a 500MB drive?). Beyond this point it should be monitored carefully and replaced when the daily rate of sector reallocations starts to increase rapidly. If a few other people post observations then these guide lines could be refined.
All in all I found the process very straight forward. The only minor surprise was that the copy of data for partition 2 took so long but doubtless there is a quicker way.
