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Offical Harddisk tool VS non-offical harddisk tool

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September 17, 2011 2:54:01 PM

I use the Acronis drive monitor to test my WD Black 1TB harddisk.
It said health only 29% and some SMART attribute failed.



Then I use WD Official lifeguard tool.



In Official tool, no error on SMART, quick test & extend test.





Which side can I trust?
a c 415 G Storage
September 17, 2011 6:30:57 PM

The problem with these utilities is that the designers take the raw numbers and apply some sort of judgement as to what's good and what's bad and just how bad its allowed to get before you should ditch the drive. And of course each designer has his own opinion.

IMHO the key is to look at the raw SMART counters to see what they're saying, understand what it is they're telling you, and make the judgement yourself.

The data lifeguard output shows some of the raw counters (you'd have to scroll down the list to see the others), and among them I see that almost 200 sectors have been reallocated. What this means is that the drive has found an area on the platters that it can't use and it's moved the data out of that area and into a spare area. The good news is that the data is now safe in the spare area. The bad news is that this obviously indicates a problem with the drive. The big question is: is the problem going to grow?

If you're paranoid, you might choose to replace the drive "just to be safe". If you're budget conscious, you might take a "wait and see" attitude. If the latter, then keep an eye on that reallocation count and watch to see if the number of sectors continues to go up. If it does, that spells trouble, and it argues for replacing the drive quickly.

Another, more serious error count is the "Pending Sectors" count. That tells you that there is data recorded in sectors but the drive hasn't been able to successfully read it. That means you have data stored on the drive that you're probably not going to be able to get back again. If that number is increasing then you should drop the drive like a hot potato.

One way or another, I'd make a definite point of getting another copy of all the data on the drive so that if it does die you won't be hooped.
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a c 311 G Storage
September 17, 2011 10:16:24 PM

Data LifeGuard is a pass-or-fail diagnostic. It does not show the RAW values of each SMART attribute, only their NORMALISED values. The figure of 188 for the Reallocated Sector Count is a normalised value. A drive that is in perfect health will have a score of 200 for this attribute. This represents zero reallocated sectors. As the number of defects grows, the normalised value decreases.

See the example in this thread:
http://www.broadbandreports.com/forum/r25949139-hard-dr...

ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
5 Reallocated_Sector_Ct 0x0033 181 181 140 Pre-fail Always - 150

The above drive has recorded 150 reallocated sectors (raw value) and has lost 19 points (= 200 - 181) from the normalised value.

My preferences for SMART tools are HD Sentinel and HDDScan.

HD Sentinel (DOS / Windows / Linux):
http://www.hdsentinel.com/

HDDScan for Windows:
http://hddscan.com/
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a c 415 G Storage
September 17, 2011 10:45:18 PM

fzabkar said:
Data LifeGuard is a pass-or-fail diagnostic. It does not show the RAW values of each SMART attribute, only their NORMALISED values.
Wow, that seems like totally unnecessarily obfuscation to me...
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a c 311 G Storage
September 17, 2011 11:06:10 PM

What do you mean by that?

Clearly you've misinterpreted DLG's output. In fact, if DLG had instead reported a value of 200 rather than 188, then you would have erroneously condemned a perfect drive. In fact I believe the OP's drive has around 100 bad sectors, not 200.

To see just how misleading the manufacturer's SMART tool can be, you only need to consider SeaTools. SeaTools doesn't even report the normalised attribute values. This means that a drive can have 2000 reallocated sectors, yet it will still be given a passing grade, without any hint that anything is wrong.
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September 18, 2011 1:03:57 AM

It is because I hear if bring the WD harddisk to HK Synnex they will use the DLG to test this harddisk. If the offical tool pass the quick test & extend test Synnex will not give the new harddisk to customer and said no damage.
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a c 311 G Storage
September 18, 2011 2:22:47 AM

FWIW, I took my old Seagate drive out of service after it had developed 120 bad sectors. It was still working fine, but I couldn't trust it any longer. Towards the end, it was developing new defects on a regular basis.

Your data, your choice.
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September 18, 2011 5:24:43 AM

sminlal said:
The problem with these utilities is that the designers take the raw numbers and apply some sort of judgement as to what's good and what's bad and just how bad its allowed to get before you should ditch the drive. And of course each designer has his own opinion.

IMHO the key is to look at the raw SMART counters to see what they're saying, understand what it is they're telling you, and make the judgement yourself.

The data lifeguard output shows some of the raw counters (you'd have to scroll down the list to see the others), and among them I see that almost 200 sectors have been reallocated. What this means is that the drive has found an area on the platters that it can't use and it's moved the data out of that area and into a spare area. The good news is that the data is now safe in the spare area. The bad news is that this obviously indicates a problem with the drive. The big question is: is the problem going to grow?

If you're paranoid, you might choose to replace the drive "just to be safe". If you're budget conscious, you might take a "wait and see" attitude. If the latter, then keep an eye on that reallocation count and watch to see if the number of sectors continues to go up. If it does, that spells trouble, and it argues for replacing the drive quickly.

Another, more serious error count is the "Pending Sectors" count. That tells you that there is data recorded in sectors but the drive hasn't been able to successfully read it. That means you have data stored on the drive that you're probably not going to be able to get back again. If that number is increasing then you should drop the drive like a hot potato.

One way or another, I'd make a definite point of getting another copy of all the data on the drive so that if it does die you won't be hooped.


I am sorry and following is the detail screen capture




I have the backup habit to the 2TB external USB harddisk but this is not possible back all change everyday.
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a c 311 G Storage
September 18, 2011 5:35:04 AM

The DLG screens do not show any raw values.

DLG will only fail your drive if any warranty-able attribute falls below its threshold. These warranty-able attributes are identified by a "1" in the Warranty column.

If you want to see the raw values, use a different SMART utility.
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a c 415 G Storage
September 18, 2011 5:36:07 AM

Sean> Wow, that seems like totally unnecessarily obfuscation to me...

fzabkar> What do you mean by that?

OK, I see what's going on - the dialogue box isn't reporting the raw values, just the normalized ones. It's not really obfuscation, it's incompleteness.

fzabkar> SeaTools doesn't even report the normalised attribute values. This means that a drive can have 2000 reallocated sectors, yet it will still be given a passing grade, without any hint that anything is wrong.

I'm the kind of guy who hates software that "dumbs down" what's really going on. I don't want my software to make assumptions for me, I want to see the what the hardware is telling me and make my own decisions. So it sounds like I'd hate SeaTools too.

Edit: It sounds like the OP is mostly interested in whether his drive can be replaced under warranty. If DLG is the tool they use to validate, then I guess that's just what he's stuck with unless he want to press them with an "angry customer" gambit.
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a c 415 G Storage
September 18, 2011 5:47:50 AM

sfawaj: It is because I hear if bring the WD harddisk to HK Synnex they will use the DLG to test this harddisk. If the offical tool pass the quick test & extend test Synnex will not give the new harddisk to customer and said no damage.

The cynic in me says that this is because DLG is the tool that's least likely to fail a drive.


fzabkar: DLG will only fail your drive if any warranty-able attribute falls below its threshold. These warranty-able attributes are identified by a "1" in the Warranty column.

Amazing to me that "Pending Sectors" isn't considered justification for a drive failure. They indicate actual data loss, the worst kind of error a drive can have short of becoming a brick, IMHO.
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a c 311 G Storage
September 18, 2011 7:25:33 AM

SMART data consist of Current, Worst, Threshold, and Raw values. You need to be aware of how the various utilities report these data.

For example, DLG's "Value" column reports 100 or 200 for most attributes. If they were raw values, then most would have been at, or close to, 0. So to answer your question as to whether your observation was "unreasonable", yes it was. Having said that, anyone watching this thread would have dismissed your error as an inconsequential brain fart, so I'm puzzled as to why you have taken umbrage at my correction.

As for why Current Pending Sectors isn't considered to be a warranty-able attribute, I suspect it's because pending sectors only become significant if they eventually become Reallocated Sectors. In fact there could be several legitimate reasons why a sector is marked "pending". For example, it could be that the write head was subject to vibration when the sector was being written, or it could be that there were adverse temperatures during writing or reading. Such sectors remain pending until the OS updates them with new data. When this happens, the HDD knows that the existing data are no longer of any value. The pending sectors are then retested and returned it to service if good. Otherwise their LBAs are reallocated to spare sectors if confirmed bad.

In short, pending sectors are not always the result of internal faults, but could be due to external factors. At least that's how I understand it.
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September 18, 2011 9:58:34 AM

I perform acronis test because I feel the harddisk performance slower than 2 months ago(new purchase?).

If the following result I test now is normal in WD black?

(all testing use windows 7 default copy tool, only one partition to another partition on same harddisk)

Test 01:

C Drive to D Drive

15420 files 3103 folders 8.97GB

take 7 mins 4 seconds to finish

average: 21.0MB /s

Test 02:

D Drive to C Drive

11 files 1 folder 6.85GB

take 2mins 37seconds to finish

average: 44.7MB/s

Test 03:

D Drive to C Drvie

1 files 1.28GB

take 23seconds to finish

average: 58.7MB/s
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a c 415 G Storage
September 18, 2011 7:27:01 PM

fzabkar said:
For example, DLG's "Value" column reports 100 or 200 for most attributes. If they were raw values, then most would have been at, or close to, 0. So to answer your question as to whether your observation was "unreasonable", yes it was. Having said that, anyone watching this thread would have dismissed your error as an inconsequential brain fart, so I'm puzzled as to why you have taken umbrage at my correction.
Yep. Brain fart. That's my story and I'm sticking to it. ;)  Sorry if I gave offense - my "obfuscation" comment was aimed at DLG, not you.


> As for why Current Pending Sectors isn't considered to be a warranty-able attribute, I suspect it's because pending sectors only become significant if they eventually become Reallocated Sectors.

If that's the case, I disagree. When a drive encounters read errors, yet is able to recover the data and move it to a spare sector, then its operating as its supposed to. But when it isn't able to recover the data, then it's in violation of the implicit trust: to store the data and deliver it back unchanged when asked. Reallocated sectors are transparent and harmless, pending sectors are destructive. My expectations when I buy a drive are that it won't loose data.

Having said that, I'm completely aware that drives aren't perfect and I don't actually trust them very far. And I've never had occasion to return a drive under warranty and probably never will unless it just plain doesn't work out of the box. But still it surprises me that a drive manufacturer wouldn't consider actual data loss to be grounds for warranty exchange. I don't think that kind of policy would stand them in good stead if it became general knowledge.
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