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Oct 12 2013

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wd caviar green load cycle count

Back in January of this year I upgraded my desktop’s hard drive to a 2 TB WD Caviar Green. Not the world’s fastest drive, but quiet, power efficient, and, so I thought, good value for money. I subsequently used two of the same disks in a new build RAID 1 server (which I must get around to writing about). An email to the ALUG mailing list this week made me check those disks.

Mark was having trouble with a RAID 5 setup and had discovered that others with the same problem were also using WD Green drives. These drives park the heads rather aggressively as part of the power saving features, Unfortunately, because RAID configurations constantly write to the disks to keep them synchronised this tends to wake the disk up as soon as the head is parked. The result is a very high load cycle count in very short order.

Having read Mark’s posts and the others like the ones referenced above, I thought I had better check my own drives (using smartctl from the smartmontools package). I didn’t like what I found.

On my desktop:

smartctl -a /dev/sda | grep Load_Cycle
193 Load_Cycle_Count 0×0032 151 151 000 Old_age Always – 148961

On the RAID server:

smartctl -a /dev/sda | grep Load_Cycle
193 Load_Cycle_Count 0×0032 071 071 000 Old_age Always – 387053

smartctl -a /dev/sdb | grep Load_Cycle
193 Load_Cycle_Count 0×0032 072 072 000 Old_age Always – 386379

WD say in their specifications for these disks that they are good for a lifetime of 300,000 Load Cycles. So my server’s disks look as if they are at high risk of failure after only 6 months usage. My desktop doesn’t look much better. Not good. Some fora I checked say that the 300,000 figure is on the conservative side and 1 million cycles is perfectly possible, but I’m inclined to believe a manufacturer’s specs in the absence of any other more authoritative advice.

I am looking for potential replacements, but meanwhile I am contemplating trying Christophe Bothamy’s linux idle3tool which supposedly may cure the head parking problem. I am not yet sure I want to use that tool in anger unless I know I have replacement disks on hand. Of course, if the tool works, then I probably would not have needed to buy any new disks.

Tricky.

Permanent link to this article: http://baldric.net/2013/10/12/wd-caviar-green-load-cycle-count/

4 comments

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  1. Juliet R. Franks

    WD Raptor has evolved! PC enthusiasts’ favorite 10,000 RPM SATA drive is now faster than ever and available in a 300 GB capacity. Engineered for maximum speed, WD VelociRaptor combines a SATA 3 Gb/s interface and 16 MB cache, to deliver performance that’s up to 35 percentage faster than its speedy older brother. With 1.4 million hours MTBF, these drives have the highest available reliability rating on a high-capacity SATA drive and are designed and manufactured to enterprise-class standards to provide enterprise reliability in high duty cycle environments.

  2. Mick

    Errrr – thanks for the advert. Sorry to have to delete your website details.

  3. David

    All of the manufacturers make drives which are optimised for RAID. For Western Digital that’s the Red series.

    I often wondered what the differences were (and why the prices differed), this is obviously one!

  4. Mick

    David

    For now (following further discussion with Mark on ALUG) I have decided to go for a seagate on the desktop and replace one of the RAID 1 disks on the server with the old WD Green from my desktop. This will give me a faster desktop drive (though, from memory of my last Seagates, probably noisier) and will also give me one drive on the RAID box which has a load_cycle_count well under half that of the other. I’ll then monitor the drives over the next 6 months to a year in the hope that I don’t lose both at once……

    (Aren’t you supposed to be working?)

    Mick

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