Last week my external harddisk (Seagate Barracuda 1.5TB in a custom enclosure) showed signs of failure (Disk Utility SMART Pre-failure status - several bad sectors) and I decided to change it. I bought a new HDD (Seagate Barracuda 2TB) and connected it to my Ubuntu box with a SATA to USB cable that could not report SMART status. I copied all the contents of the old HDD to the new HDD (one partition with rsync, the other with parted cp) and then gently replaced the old HDD with the new one inside my aluminum enclosure.

For obscure reasons after reconnecting the new HDD through the old enclosure, the Linux box could not detect my partitions. I recovered the partitions with testdisk and restarted the computer. After the restart I checked the SMART status of the new HDD an I get this:

Read Error Rate
Normalized 108

Worst 99

Threshold 6

Value 16737944

I got a high value on the Seek Error Rate as well. Wondering why this happens I copied 2 GB directory from one partition to the other and rechecked the SMART status (5 minutes later). This time I got the following:

Read Error Rate
Normalized 109

Worst 99

Threshold 6

Value 24792504

As you see there has been an increase in the error rate. I am unable to interpret these numbers. Is my new hard disk already dying? What are the acceptable values in these fields for Seagate hard disks? Then why the assessment is still good?

While I could get temperature and airflow temperature data from my old HDD, I can not fetch them for the new one. I noticed that my old hdd had got really hot sometimes. Is it possible that the enclosure is killing the harddisks due to high temperature?...



As far as heat goes, when the temperature of a hard disk rises by 10°C, it becomes twice as much less reliable. The normal recommended working temperature of a hard disk is 35-40°С. So if it rises above that, A lot of things can happen, like data corruption and data loss to crashes and even hardware failures.

Read Error Rate S.M.A.R.T. parameter indicates the rate of hardware read errors that occurred when reading data from a disk surface. Any value differing from zero means there is a problem with the disk surface, read/write heads (including crack on a head, broken head, head contamination, head resonance, bad connection to electronics module, handling damage). The higher parameter’s value is, the more the hard disk failure is possible.

This is a critical parameter. Degradation of this parameter may indicate imminent drive failure. Urgent data backup and hardware replacement is recommended.1

Now Seagate suggests that you use there test utility, and if the drive passes they claim that its OK. For information on how to use that in Ubuntu see Ubuntu Forums.


  • I read the exact same lines on the Acronis website, but I found the non-zero condition a little bit exaggerated given then none of my 6 harddisks installed in 4 computers show a zero value there (except my SSD of course). I assumed Disk Utility reports the values differently... Aug 4 '12 at 20:00
  • Btw, SEATOOLS is windows only, my drive is formatted ext4. Aug 4 '12 at 20:06
  • See the Ubuntu forums link, it shows you how to test with seatools.
    – Mitch
    Aug 4 '12 at 20:09

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