Help with WD Caviar Green problems ...

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ist.martin
Posts: 220
Joined: Fri Jul 18, 2003 11:59 am
Location: Vancouver, B.C.

Help with WD Caviar Green problems ...

Post by ist.martin » Sat Jan 22, 2011 9:34 am

Hello all:

I have been imaging my system onto an external, eSATA 1TB WD Caviar Green drive. It used to take about 2 1/2 hours to clone my 640GB system disk onto the Green.

This week, the imaging slowed to a glacial pace. I ran HDTune on my drives, and noticed that the throughput onto the 1TB drive is just 3.8 MBPs (my system drive, also SATA, is 110 MBps). So I assumed I have an eSATA problem, and suspended the drive (using an Antec Solo) internally using a straight SATA cable. No change. I am still getting the low throughput.

If I check the drive 'Health' with HDTune it shows that my 'Ultra DMA CRC Error Count' is 89 for the 1 TB drive (0 for my system drive). Is it a faulty drive? Faulty configuration? Anything else I should check/set?

Sorry, I don't know much about these things, and this is the only tech/PC forum that I post on. Any help would be greatly appreciated.

HFat
Posts: 1753
Joined: Thu Jul 03, 2008 4:27 am
Location: Switzerland

Re: Help with WD Caviar Green problems ...

Post by HFat » Sat Jan 22, 2011 10:18 am

The first thing I'd do is to copy everything that matters off the drive. If you don't already have copies of the data elsewhere, copy what matters most first.

When the data is safe, you can worry about the drive. It looks like it's defective. There are disgnostics you can run (I use the smartmontools).
You could try to put it in a different PC to rule out weird software problems and the like. Or you could disconnect your system drive and boot from a live CD or something. There are live CDs such as Clonezilla which come with smartmontools.

ist.martin
Posts: 220
Joined: Fri Jul 18, 2003 11:59 am
Location: Vancouver, B.C.

Re: Help with WD Caviar Green problems ...

Post by ist.martin » Sat Jan 22, 2011 11:26 am

Thanks for the help. There is currently nothing on the drive. I was using it as a backup, and it got repartitioned when I started a new one, and I aborted the backup.

Is there some definitive test I can do to see if the drive is the problem? It does appear to read and write fine, just crazy slowly. Is there some subtle setting somewhere I may have triggered that kills the throughput? Is it possible that I have a problem with one of the SATA ports on my motherboard?

Thanks.

HFat
Posts: 1753
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Location: Switzerland

Re: Help with WD Caviar Green problems ...

Post by HFat » Sat Jan 22, 2011 11:45 am

There are settings which affect the throughput... but settings which "kill" it like that? Not to my knowledge.

Once again: to rule out software issues and even more improbable stuff like issues with a SATA port or a cable, try the problem drive in another PC. Or you could replace your main drive with the problem drive and boot a LiveCD.

You could run a long SMART test and post the result here. It wouldn't be a definite test but it's probably the best you could do. There may be more user-friendly tools but this is what I'd do:
To run the test (feel free to abort if it's going nowhere): smartctl -t long [drive]
To watch the test's progress and get the current status of the drive along with the test results: smartctl -a [drive]
Replace "[drive]" with "hdb" if you run Windows and have two drives connected (the system drive and the problem drive).

Mankey
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Re: Help with WD Caviar Green problems ...

Post by Mankey » Sat Jan 22, 2011 12:55 pm

Check to see if your partition is aligned properly.

Some of the new WD Green drives require different partition alignment.

This is a good article about the new requirements for partition alignment on modern drives.
http://www.anandtech.com/show/2888/2

If you partition isn't aligned properly, you WILL notice much slower transfer rates are you are describing.

HFat
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Location: Switzerland

Re: Help with WD Caviar Green problems ...

Post by HFat » Sat Jan 22, 2011 1:09 pm

There's no way misaligned sectors will give you a *96.5%* performance impact on a hard drive. There isn't much of an impact for sequential operations anyway.

ist.martin
Posts: 220
Joined: Fri Jul 18, 2003 11:59 am
Location: Vancouver, B.C.

Re: Help with WD Caviar Green problems ...

Post by ist.martin » Sat Jan 22, 2011 2:05 pm

Mankey:

Thank you, thank you, thank you.

It turns out that is exactly my problem! I am using XP and my backup drive is a 1TB WD Green Power - one of the 'EARS' drives.

I downloaded WD specific image/backup software from Western Digital at:

http://support.wdc.com/product/download ... 08&lang=en

I repartitioned my disk using their tool, and voila, I'm back up to 80MBps throughput. It boggles my mind that a misaligned sector could have that sort of impact - it makes no sense.

I did a lot of googling, and never found that on my own. I'll bet there have been hundreds or more WD disks RMA'ed by XP users! Must be a nightmare for them.

fastturtle
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Re: Help with WD Caviar Green problems ...

Post by fastturtle » Mon Jan 24, 2011 10:18 am

The reason the misalignment caused problems is that the drive used the new 4K boundary instead of the 512b system that XP understands. Thus an Alignment issue such as this can and does cause major performance issues.

I suspect what happened was that the Repartitioning defaulted to the new 4k cluster boundary, thus screwing things up for XP and yes this is going to be a growing problem that people will see as XP enters extended support status - support ends in 2014, which is another 3 years folks.

HFat
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Location: Switzerland

Re: Help with WD Caviar Green problems ...

Post by HFat » Mon Jan 24, 2011 11:39 am

People have been benchmarking misaligned drives and been getting virtually the same sequential throughput as when they're aligned correctly.
It could be an HDTune bug or a WD bug (or "feature"). I avoid WD drives myself so I don't know. But there's no way in hell misalignment as such could have that impact. Use yar brainz people!

ist.martin
Posts: 220
Joined: Fri Jul 18, 2003 11:59 am
Location: Vancouver, B.C.

Re: Help with WD Caviar Green problems ...

Post by ist.martin » Mon Jan 24, 2011 12:08 pm

HFat wrote:People have been benchmarking misaligned drives and been getting virtually the same sequential throughput as when they're aligned correctly.
It could be an HDTune bug or a WD bug (or "feature"). I avoid WD drives myself so I don't know. But there's no way in hell misalignment as such could have that impact. Use yar brainz people!
"It could be an HDTune bug" wtf???

As I posted already, after repartitioning using WD's software, it took me 2 hour to image onto the drive. Before the repartitioning it was taking about 40 hours. HDTune gave me 3.8MBps throughput before the repartitioning, and ~ 70-80 MBPs after. Which adds up.

I don't know anything about the details of all this. But I do know that using their tool increased my throughput by 2000%.

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