Knowledgebase: NAS Management
Why my disk shows warning even after bad block scan?
Posted by - NA -, Last modified by on 24 September 2010 21:57
The warning message is depend on the HDD built-in SMART diagnosis function, once Current Pending Sector or Reallocated Sector Count have any value (not equal 0), system would mark this HDD as WARNING to notify user.

[Firmware version < 2.01.xx]
Reallocated Sector >=1 show warning
Current Pending sector >=1 show warning

[Firmware version > 2.01.xx]
Reallocated Sector >=32 show warning
Current Pending sector >=1 show warning

[Firmware since 2011]

Due to there were different judgment standard from different harddisk vendors, the newere firmware didn't show "Warning" in the [Disk Information] page, instead of this information, user may click "S.M.A.R.T." to find the S.M.A.R.T. infromation of the disks.

[About S.M.A.R.T. information]

The Current Pending Sector & Reallocated Sector Count means this HDD have bad sector or going to bad sector soon, thus we need arrange new HDD for replacement. Please refer to our online knowledge base,

Do bad block scan won't change the HDD status from warning to OK because the unit read S.M.A.R.T. infro from HDD itself.

For diagnostic tools, please refer to the following links,

Hitachi Drive Fitness Test

Samsung HUTIL

Seagate / Maxtor SeaTools

WD Data Lifeguard Diagnostic for Windows

However, even if the result of S.M.A.R.T. is healthy or the values are located in acceptable range; hard disk might be fault without any symptom. According to the research from Google (, after the first scan error, drives are 39 times more likely to fail within 60 days than drives without scan errors. We strongly recommend that the important information must always be backed up.

We strongly recommend using enterprise-class hard drives. In the hard drive manufacturer's web site, we also found that hard disk's manufacturers do not recommend using low power desktop models for RAID or NAS. For example: WD official Datasheet (

- Business Critical RAID Environments – WD Caviar Green Hard Drives are not recommended for and are not warranted for use in RAID environments utilizing Enterprise HBAs and/or expanders and in multi-bay chassis, as they are not designed for, nor tested in, these specific types of RAID applications. For all Business Critical RAID applications, please consider WD's Enterprise Hard Drives that are specifically designed with RAID-specific, time-limited error recovery (TLER), are tested extensively in 24x7 RAID applications, and include features like enhanced RAFF technology and thermal extended burn-in testing.

keyword: smart hdd harddisk failure WD Seagate Hitachi Samsung Fujitsu Toshiba warning
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