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Frequent Visitor
thepregnantgod
Posts: 2
Registered: ‎06-20-2011
0

3TB Green Drive Spindown - RAID?

Okay, okay, for those of you who hate RAID.  Got it.  For those of you who tolerate RAID questions, I look to you for guidance.  

 

I currently have 4 3TB Green Caviar drives and would like to put them on an external RAID controller (Rocketraid 2300) in a RAID 5 configuration.  I know that to reduce power consumption the Green drives have variable spin rates.  However, on some of my other non-WD drives there were settings/firmware/bios or something where you could control whether the drive would go into a sleep mode/slow down.

 

So...my questions:

 

1. Does anyone have experience with 3TB Green drives in RAID configuration?

2. Is there a way to control the slow down/spin down on these drives?

 

Thank you in advance.

Honored Contributor
RoofingGuy
Posts: 2,871
Registered: ‎08-30-2010
0

Re: 3TB Green Drive Spindown - RAID?

 


thepregnantgod wrote:

Okay, okay, for those of you who hate RAID.  Got it.  For those of you who tolerate RAID questions, I look to you for guidance.  

 

I currently have 4 3TB Green Caviar drives and would like to put them on an external RAID controller (Rocketraid 2300) in a RAID 5 configuration.


 

It has nothing to do with whether I "hate" RAID or not, but I would strongly suggest to re-think things.

 

The Caviar Green drives are not RAID drives.  People keep trying to use them anyways, because they're cheap, and then have no end to the problems.  These boards are full of people who've tried using Caviar drives in a RAID 5 array and it hasn't worked, or the controller just marks the whole drive as "bad" when it drops out of the array.

 

 

 

WD desktop hard drives (Caviar Black, Green, and Blue) have been tested and are recommended for consumer RAID applications when using the drives in a RAID 0 (Stripe) or RAID 1 (Mirror) configuration.

...

Critical: WD Caviar Black, Caviar Green, and Caviar Blue 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.

http://wdc.custhelp.com/app/answers/detail/a_id/996/

 

 

If you install and use a desktop edition hard drive connected to a RAID controller, the drive may not work correctly. This is caused by the normal error recovery procedure that a desktop edition hard drive uses.


When an error is found on a desktop edition hard drive, the drive will enter into a deep recovery cycle to attempt to repair the error, recover the data from the problematic area, and then reallocate a dedicated area to replace the problematic area. This process can take up to 2 minutes depending on the severity of the issue. Most RAID controllers allow a very short amount of time for a hard drive to recover from an error. If a hard drive takes too long to complete this process, the drive will be dropped from the RAID array. Most RAID controllers allow from 7 to 15 seconds for error recovery before dropping a hard drive from an array. Western Digital does not recommend installing desktop edition hard drives in an enterprise environment (on a RAID controller).


Western Digital RAID edition hard drives have a feature called TLER (Time Limited Error Recovery) which stops the hard drive from entering into a deep recovery cycle. The hard drive will only spend 7 seconds to attempt to recover. This means that the hard drive will not be dropped from a RAID array. While TLER is designed for RAID environments, a drive with TLER enabled will work with no performance decrease when used in non-RAID environments.

http://wdc.custhelp.com/app/answers/detail/a_id/1397/



 

 

So... if you go ahead and do it anyway, despite WD telling you up front that the drive may not work correctly, there's very little anyone can do in the way of help to try and get it working correctly when things go badly.

Frequent Visitor
thepregnantgod
Posts: 2
Registered: ‎06-20-2011
0

Re: 3TB Green Drive Spindown - RAID?

First, thanks for the response.  When I mentioned RAID haters, it was directed at those who view RAID as too risky no matter the drive being used.  Your comments are directed toward using Green drives in a RAID array despite WD's warnings not to.

 

I've read many, many articles on the TLER issue and understand it.

 

My final question, if you can answer this, is: does the TLER issue lessen/become moot if the RAID is actually a "software" RAID?  I've read some posts that TLER on Green drives becomes an issue when the RAID controller drops the drive and that software RAID does not do this.  Is this true?

 

If so, then is it safe to assume that my RAID card is in fact software RAID since it isn't recognized in BIOS but only once Windows loads the driver, it has no cache or BBU, etc.?

 

Thanks.

Frequent Advisor
rtguille
Posts: 65
Registered: ‎03-26-2011
0

Re: 3TB Green Drive Spindown - RAID?

> My final question, if you can answer this, is: does the TLER issue lessen/become moot if the RAID is actually

> a "software"

> RAID?  I've read some posts that TLER on Green drives becomes an issue when the RAID controller drops the drive and

> that software RAID does not do this.  Is this true?

 

Certainly, the greenies should not be used in hardware raid or in fakeraids (at least in my opinion).

 

Regarding software, i se no problem with software raid (aka, some form of volume manager, mdadm, lvm, VxVM).

 

The point is that fakeraids are mixed beasts because it is the bios which first handles the disks/raid (and tries to behave like a hardware raid, but uses the CPU & RAM for computations). Then the operating system (mostly Win) loads a software driver and it is that software that 'continues' handling the driver. Both component, the Fakeraid_BIOS and the OS_Fakeraid_Driver are able to understand the specific controller metadata. But this scheme is much less flexible than software raid. If you use windows and cannot afford a good HBA (lsi, adaptec, etc with it's own CPU+RAM and even cache battery) and enterprise disks (not just TLER but other features) your only option for using raid with the C: drive are fakeraids.(sis / nvidia / intel, etc, etc. and even for different motherboard vendors/model)

 

I do not have any issue with software raid (mdadm/linux), with blacks, greens. And i know of some greens with more than a year and a half uptime in 'perfect health' wirth mdadm/linux. (i got surprised when i looked they smarctl data)

 

I feel that the TLER  is being abused by the marketing people. There is a lot of confused people. The people that do not know, keep not knowing/caring. The people who know, well just knows. And te people that is learning, and posseses certain level of knowledgebut does not master a field (example, storage knowledge) are being forced to learn in the hard way. (for example, using 2 blacks for fakeraid on a supported controller with supported drives and supported usage by wd and finding that it does not work.)

 

I your case:

* update to tha latest BIOS/UEFI + Fakeraid Card Firmware

* update the operating system drivers (all, video, chipset, etc, ALL)

Try again, if fails:

* jumper all drives to a lower sata link speed.

* also, since you have 4 drives (or more?), i think you should use the "power on in standby" feature. Your controller seems to support "Staggered Drive Spinup".

 

 

 

 

 

 

 

 

 

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