I'm running badblocks in parallel on 2 identical hard drives. The problem is that /dev/sda has already finished without error the tests but /dev/sdb it at 363353920/488386583 (about 75%) but didn't report any error.

Is this a sign of hdd failure?

The tests are running from an emergency console and the server is dual E5520. Also the both HDD are from RAID1 array so the reads and writes were presumably identical.

Thanks for your answers.