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I`ve got a real funky response from WD support today, i`d like to share here. This is just too weird.... After asking if they could give a comment if the problem with the high Load_Cycle_Count may be an issue of their drives or an issue of Linux i got: ------ Dear...... The problem is, that we actually don`t use the disks with Linux. I´m sorry that i cannot send further information to you. Sincery yours <insert support employee name here> Western Digital Service and Support ------ (translated from german) So, WD sells enterprise SATA disks, optimizied for 24/7 & Raid array usage, but they don`t seem to actually test them with Linux or at least are not able to "support" Linux usage....... --
Well the answer was probably just from a first level support person so nothing one should get excited about. Anyway to the high Load_Cycle_Count; if I understood the technology correctly the WD GreenPower drives are exactly "Green" because they unload the heads on a plastic ramp (no landing zone!) quite often during longer idle periods. Thus they can power off the positioning logic and actuator of the heads. -> safe Power This also explains why the power usage under seek is comparable with other "non-green" drives... my 1 TB drive has also a relative high value: 193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 2786 Just my 2 cents, Arnd || --
I don't find it Green when I have to buy new disks because of ramp or LZ, it's quite a force with which the head is parked. --
Well I'm no expert, but I would say comparing to the normal wear out due to use (seeking, bearing wear out, vibrations, spin up, bumps) the factor of a controlled unload/load cycle on a plastic ramp is probably negligible. BTW: my hitachi notebook drive, which I believe has a similar And it didn't fail on me yet... Of course this is just one data point. Regards, Arnd Hannemann --
Practically nobody has any on-line support that means anything anymore. The person who wrote the response is probably in the Philippines, makes about $US 3.00 per hour, and is allowed to pee twice a day. Don't worry. The tiny "bump-proof" drives cycle on an off many times to conserve power. They also keep the heads from landing "crashing" by inserting a plastic wedge between the swing-arms during power down. It's probably a lot less harmful than letting the heads touch down somewhere. It's not just the positioning logic that gets powered off. The discs are spun down, which saves a lot of power. Cheers, Dick Johnson Penguin : Linux version 2.6.22.1 on an i686 machine (5588.29 BogoMips). My book : http://www.AbominableFirebug.com/ _ **************************************************************** The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. --
And drives latencies into the skies. Not to mention that the permanent spinups and downs also affect life. --
Yes. Maybe there is a way to turn if off? That's why we should be able to get somebody from WD who will answer a Linux question, instead of the usual on-line "help." I'm going to poke around and see if I can find a real person at WD. Cheers, Dick Johnson Penguin : Linux version 2.6.22.1 on an i686 machine (5588.29 BogoMips). My book : http://www.AbominableFirebug.com/ _ **************************************************************** The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. --
It took about 3/4 hour to access their web-page and get a question submitted. It has been my experience that companies that don't maintain their web-pages, don't really care about customers. My query was, "How do I turn off Green Power so I don't have the horrible latencies on virtual memory systems that have active swapping?" In the unlikely event that they answer me, I will put the answer on this list. My guess is that if they do answer me, the answer will be, "Duhh?" We'll see. Cheers, Dick Johnson Penguin : Linux version 2.6.22.1 on an i686 machine (5588.29 BogoMips). My book : http://www.AbominableFirebug.com/ _ **************************************************************** The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. --
The only answer I got was the "canned" answer about contacting your hardware and software vendor. There don't seem to be any humans employed there, anymore. That's unfortunate because Lake Forest, California is a nice place. Cheers, Dick Johnson Penguin : Linux version 2.6.22.1 on an i686 machine (5588.29 BogoMips). My book : http://www.AbominableFirebug.com/ _ **************************************************************** The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to DeliveryErrors@analogic.com - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. --
I wrote a few notes about load cycles here: http://www.pixelbeat.org/docs/hard_disk_reliability/ It's bad that the WD GreenPower doesn't support `hdparm -B` setting its parameters, but I found I didn't need to tweak these anyway. I just got the distro to write less often to the drive with the (rel)atime mount options. With that I got an acceptable load cycle rate. Pádraig. --
The problem is not how often Linux wakes the head up due to writes of any sort, but how often the head decides to go down without our consent. --