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Choosing the right drives for my Drobo 5D
01-04-2013, 09:38 AM (This post was last modified: 01-04-2013 09:40 AM by Paul.)
Post: #11
RE: Choosing the right drives for my Drobo 5D
thanks for the info guys, (and another picture too)
i saw the left and right arrows next to it and took a guess it was for other drives too Smile
btw ive been using greens in all my drobos and no problems so far.
also others have used greens here too.. is the red better for the 5D unit in particular?

(btw i have XP home SP2, a Drobo v1 with 2x 1TB/2x 1.5TB WD greens, & a bkp Drobo v2 with the same + a DroboShare: unused)
& a DroboS v2 with 3xWD15EADS &2x1TB in DDR mode on win7, & a drobo5D (all usb)
  • btw i did a sustained (write) operation for about 6 hours, and got 13.2MB / sec ...objection? "sustained" :)
    (16.7MB/s on a v2 & 47-96MB/s drobo-s)
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01-04-2013, 09:52 AM
Post: #12
RE: Choosing the right drives for my Drobo 5D
(01-04-2013 09:38 AM)Paul Wrote:  thanks for the info guys, (and another picture too)
i saw the left and right arrows next to it and took a guess it was for other drives too Smile
btw ive been using greens in all my drobos and no problems so far.
also others have used greens here too.. is the red better for the 5D unit in particular?

No they are better for any type of raid systems. Not only for the way they handle parking the drive heads but because the TLER is designed for RAIDS and have less of a chance of putting a unit into rebuild mode or out right bricking the array due to timeouts and long seeks. Also 24x7 extended warranty's and support vs standard desktop warranty. Life expectancy is far greater and they are designed for 24x7 use.

AnandTech - Western Digital Red Review: Are NAS-optimized HDDs Worth the Premium?

and

Tim'sHardware -
Western Digital Red: NAS-Specific SATA 6Gb/s Drives, Reviewed
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01-04-2013, 10:47 AM
Post: #13
RE: Choosing the right drives for my Drobo 5D
thanks some interesting facts there, and seems to be good for the low power and temperature values too

(btw i have XP home SP2, a Drobo v1 with 2x 1TB/2x 1.5TB WD greens, & a bkp Drobo v2 with the same + a DroboShare: unused)
& a DroboS v2 with 3xWD15EADS &2x1TB in DDR mode on win7, & a drobo5D (all usb)
  • btw i did a sustained (write) operation for about 6 hours, and got 13.2MB / sec ...objection? "sustained" :)
    (16.7MB/s on a v2 & 47-96MB/s drobo-s)
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01-04-2013, 10:54 AM
Post: #14
RE: Choosing the right drives for my Drobo 5D
(01-04-2013 10:47 AM)Paul Wrote:  thanks some interesting facts there, and seems to be good for the low power and temperature values too

And they are dead quiet and smooth even when on a complete load.
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01-05-2013, 10:46 AM
Post: #15
RE: Choosing the right drives for my Drobo 5D
When I first heard about Red drives I thought - "this is great, Raid 5 compatibility at near consumer (green) prices".

But the more I look into it, the less I like....

Primarily, I am not convinced there is anything significantly different with the TLER issue. If there were, then there should be other classes of devices on WD's compatibility list, and many more makers recommending them.

When I look at the compatibility list, what I see are only devices that are also compatible with Green drives. On the DAS end the only device I see listed is the Drobo, and everyone here knows that that has always been Drobo's major claim to fame. Did I miss something there?

On the NAS side, I suspect all those NAS boxes are using Linux MDADM for the Raid 5 architecture and as far as I know, MDAMD has always been considered OK for Raid 5. Since most Linux support is "user supplied" via Linux support forums, the whole idea of what is or isn't "compatible" is murky simply because as a free product no one is actually putting money (in the form of warranty and risk of returns) behind Linux recommendations.

But the NAS makers, who are simply writing GUI interfaces over standard Linux, have come around to adding Green drives to their compatibility lists and I am not aware of any reliability caveats.

I have a Sans Digital 4 bay USB/eSata Raid/JBOD enclosure. I know for a fact that they do not recommend Red drives and have specifically said so on their support forum when the question came up. I assume this is the case for other DAS striped Raid boxes but I have only done some cursory checking. But I do not see any other DAS boxes on WD's compatibility list. For this reason I do not use my Sans Digital box for Raid5 use, only in JBOD mode.

If I am correct in the above, then what is the real value of the Red drives in terms of the TLER issues, or any other related issues that might make a consumer drive fail in a Raid5 system?

On the other hand, WD specifically recommends NOT using Red drives in a JBOD type application, and I can understand why- the same reason Enterprise drives can cause problems in JBOD arrangements.

I have always semi-retired older Drobo drives as offline JBOD backup. And sometimes they might get tasked to spin in my internal server bays when I need some additional online storage outside the Drobo. Since I keep 4 copies of all my important data, any drive upgrades are 4x the cost, so I can't afford to totally replace all my drives when their function changes or I need an incremental capacity upgrade.

What I said above has some contradictions, depending on how you look at it- if the Reds have no real additional value then they should be fine for JBOD use, and if they are not fine for JBOD use they should add great value to a Raid device. I just can't distinguish facts from marketing drivel and when it comes to hi-tech marketing claims I am definitely from Missouri.

Any thoughts on this?

_____________________________________________________
Drobo S (V1) 2x2TB WD20EARS 1x2TB WDEARX 1x1.5TB WD15EARS 1x1TB WD10EADS
Single Disk Redundancy (for the time being)
WinXP SP3 via USB2.0
Win7 Pro, via Rosewill RC-219 eSata HBA
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01-05-2013, 12:02 PM
Post: #16
RE: Choosing the right drives for my Drobo 5D
(01-05-2013 10:46 AM)NeilR Wrote:  When I first heard about Red drives I thought - "this is great, Raid 5 compatibility at near consumer (green) prices".

But the more I look into it, the less I like....

Primarily, I am not convinced there is anything significantly different with the TLER issue. If there were, then there should be other classes of devices on WD's compatibility list, and many more makers recommending them.

When I look at the compatibility list, what I see are only devices that are also compatible with Green drives. On the DAS end the only device I see listed is the Drobo, and everyone here knows that that has always been Drobo's major claim to fame. Did I miss something there?

On the NAS side, I suspect all those NAS boxes are using Linux MDADM for the Raid 5 architecture and as far as I know, MDAMD has always been considered OK for Raid 5. Since most Linux support is "user supplied" via Linux support forums, the whole idea of what is or isn't "compatible" is murky simply because as a free product no one is actually putting money (in the form of warranty and risk of returns) behind Linux recommendations.

But the NAS makers, who are simply writing GUI interfaces over standard Linux, have come around to adding Green drives to their compatibility lists and I am not aware of any reliability caveats.

I have a Sans Digital 4 bay USB/eSata Raid/JBOD enclosure. I know for a fact that they do not recommend Red drives and have specifically said so on their support forum when the question came up. I assume this is the case for other DAS striped Raid boxes but I have only done some cursory checking. But I do not see any other DAS boxes on WD's compatibility list. For this reason I do not use my Sans Digital box for Raid5 use, only in JBOD mode.

If I am correct in the above, then what is the real value of the Red drives in terms of the TLER issues, or any other related issues that might make a consumer drive fail in a Raid5 system?

On the other hand, WD specifically recommends NOT using Red drives in a JBOD type application, and I can understand why- the same reason Enterprise drives can cause problems in JBOD arrangements.

I have always semi-retired older Drobo drives as offline JBOD backup. And sometimes they might get tasked to spin in my internal server bays when I need some additional online storage outside the Drobo. Since I keep 4 copies of all my important data, any drive upgrades are 4x the cost, so I can't afford to totally replace all my drives when their function changes or I need an incremental capacity upgrade.

What I said above has some contradictions, depending on how you look at it- if the Reds have no real additional value then they should be fine for JBOD use, and if they are not fine for JBOD use they should add great value to a Raid device. I just can't distinguish facts from marketing drivel and when it comes to hi-tech marketing claims I am definitely from Missouri.

Any thoughts on this?

This is a very simplified.

Well JBOD is not a real raid it stores data normally across a single disk so the timeouts and other issues that a normal raid would encounter would not apply. Which in the same state a drive with TLER set to on and in a JBOD when data is requested and it took to long it would assume the data is on another drive and stop seeking which then would crash the system since in a JBOD system there is only one copy on one drive.

This issue is with RED's or Enterprise drives are that when a data request is sent to the array it knows not to hold up the controller since it knows that there will be another copy that can be fetched if an error or issue finding the data comes up.

If a green or consumer drive is in an array the drive can continue to loop looking for the data not knowing that it is holding up the controller then the controller will then assume the drive failed since it has not handed the data or the task back to the controller to look elsewhere causing the raid array to go into rebuild or outright crash.

What is catching you up is i belive you think JBOD is a true RAID which it is not it is "Just A Bunch Of Disks" with no speed or redundancy. A RED would also not work as a single drive in a system it would also cause allot of crashes and corruption.
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01-05-2013, 12:32 PM
Post: #17
RE: Choosing the right drives for my Drobo 5D
masc2279, I do understand that JBOD is just one drive, with no redundancy, and I also understand why a JBOD disk is best used with a long error error recovery cycle. With the short cycle of an enterprise Raid drive (7 seconds or less), it may give up and necessarily see corrupted data when a longer recovery attempt might have recovered the data, and allowed the disk's firmware to relocate that bad sector.

I also understand that most Raid controllers will only wait about 7 seconds for the disk to return either the data or a "sector failed" signal, or however it does that under various circumstances. With a consumer drive, the drive may still be trying to recover a sector long after the Raid controller "times out", deciding that the drive has totally failed and become non-communicative.

Did I state that accurately, at least at the simplest level?

My issue is this: if Red drives really work like Enterprise drives then why are they not suitable for all Raid devices that require short error recovery cycles? For example, my Sans Digital TR4UTBN DAS box?

And further, after reviewing the WD compatibility list I fail to see any device listed that does not already fully support Green drives. That generally includes the Drobos DAS boxes and all the Linux based NAS boxes. The compatibility list DOES NOT include any devices (to my knowledge) that do not already support Green drives.

The Red drives seem to be neither fish nor fowl, and it is not clear to me exactly what species they are trying to emulate.

_____________________________________________________
Drobo S (V1) 2x2TB WD20EARS 1x2TB WDEARX 1x1.5TB WD15EARS 1x1TB WD10EADS
Single Disk Redundancy (for the time being)
WinXP SP3 via USB2.0
Win7 Pro, via Rosewill RC-219 eSata HBA
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01-05-2013, 01:34 PM
Post: #18
RE: Choosing the right drives for my Drobo 5D
(01-05-2013 12:32 PM)NeilR Wrote:  masc2279, I do understand that JBOD is just one drive, with no redundancy, and I also understand why a JBOD disk is best used with a long error error recovery cycle. With the short cycle of an enterprise Raid drive (7 seconds or less), it may give up and necessarily see corrupted data when a longer recovery attempt might have recovered the data, and allowed the disk's firmware to relocate that bad sector.

I also understand that most Raid controllers will only wait about 7 seconds for the disk to return either the data or a "sector failed" signal, or however it does that under various circumstances. With a consumer drive, the drive may still be trying to recover a sector long after the Raid controller "times out", deciding that the drive has totally failed and become non-communicative.

Did I state that accurately, at least at the simplest level?

My issue is this: if Red drives really work like Enterprise drives then why are they not suitable for all Raid devices that require short error recovery cycles? For example, my Sans Digital TR4UTBN DAS box?

And further, after reviewing the WD compatibility list I fail to see any device listed that does not already fully support Green drives. That generally includes the Drobos DAS boxes and all the Linux based NAS boxes. The compatibility list DOES NOT include any devices (to my knowledge) that do not already support Green drives.

The Red drives seem to be neither fish nor fowl, and it is not clear to me exactly what species they are trying to emulate.

Where did you get that you cannot use WD RED's. I just looked and i can get them pre configured with WD RED's from many different suppliers including NewEgg and My CDW corporate account also shows it. Now the model for the unit is TR4UTBPN not TR4UTBN maybe they corrected the issues but there is nothing to keep you from using RED's from what i see i can call and find out on monday if needed.
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01-05-2013, 02:48 PM (This post was last modified: 01-05-2013 02:52 PM by NeilR.)
Post: #19
RE: Choosing the right drives for my Drobo 5D
(01-05-2013 01:34 PM)masc2279 Wrote:  Where did you get that you cannot use WD RED's. I just looked and i can get them pre configured with WD RED's from many different suppliers including NewEgg and My CDW corporate account also shows it. Now the model for the unit is TR4UTBPN not TR4UTBN maybe they corrected the issues but there is nothing to keep you from using RED's from what i see i can call and find out on monday if needed.

Now we're going to get into the HUGE SCAM involving cheap consumer Raid boxes and green drives...

I just searched Newegg and do not see any drive bundles listed for the TR4-UTBP(N). However, I frequently see that box listed with WD GREEN drives on their daily Shell Shocker deals and on their regular specials emails and web site lists. I just don't recall seeing them listed with Red drives.

I did not check CDW and really it is not important; what I have to say about NewEgg says it all.

I have seen the same with other "Raid boxes" such as CineRaid, MediaSonic, and NewEgg's Rosewill house brand. They are all sold from time to time bundled with Green drives. They are all sold under the "Raid" category on NewEgg. The web page descriptions include "Raid" prominently in the product heading and related marketing romance text. Only in small letters, buried deep, do you even see a mention of the word "JBOD".

You will NEVER, EVER, see any warning or caution in NewEgg's product page indicating that Green drives should not be used with the Raid-5 configurations for which these boxes are primarily marketed. Ever. I defy you to post a link proving me wrong on this. Edit: Nor will you see this on Sans Digital's product page!

I bought my TR4-UTBPN from NewEgg in June 2011. I wasn't sure if I wanted to run it as Raid5 or JBOD but I liked the idea that it could go either way, and the Raid performance was supposed to be pretty good, and that, at the time, was unusual for USB Raid boxes since most of them have underpowered processors (all us old Drobo V2 users understand that problem!).

Before I bought it, I downloaded the manual which you can see here:

http://dl.sansdigital.com/images/downloa...http://dl.sansdigital.com/images/downloads/TR4UT-BP_TR4UTP/TR4UTBP_TR4UTP_Detailed_

That manual, on page 48, includes a hardware HCL that clearly lists WD GP drives without any caveats. IOW I did my homework, read the manual, and it clearly indicated GP drives were compatible.

After I bought the unit I did more research on their former support forum. One of the reasons I bought a Sans Digital was that they have had a very active support forum, where the alternative vendors generally have no forum and their published web site technical data is sparse and leaves much to the imagination. In particular the issue of drive compatibility.

Unfortunately Sans Digital appears to have killed their support forum; I cannot find it on their site links or in a google search. I'm not impressed, to say the least. However...

What I saw on their support forum is that a lot of users were discussing their Green drives in their Raid 5 arrays. Many were happy, but some were there to try to find their way out of an array crash. And in every case, the Sans Digital official support rep had one and only one thing to say: "We only support Enterprise Level Drives for Raid-5 on these devices".

So I posted a note asking why this was not documented in the manual, which clearly listed Green drives without any caveat.

The answer I got was something along the lines of... "sorry, but that is in error and we are in the process of updating the manual".

And shortly after my post, the link to the manual was removed from the product page. Well, it's over a year later and that link is back, as well as the same version of the product manual, with the same HCL on pg 48, still listing Green drives as compatible.

It became clear to me that the marketing of these boxes was strongly encouraging consumers to couple them with Green drives and set up Raid-5 arrays. Everything works great- until the first sector error, when the array would rebuild. And then, for whatever reason, that appeared to have a tendency to end with multiple drives dropping from the array and array losses.

At that point, the box maker, via tech support, informs the hapless owner (who, in most cases, just lost a few TBs of data) that his $100 box needs 4x $300 drives instead of 4x $100 drives. Usually too late for our hapless consumer.

I blame NewEgg for this scam too, and I like NewEgg and I use them for a lot of my computer related purchases. But in this way they are very dishonest. But they are just following the lead of the box makers.

Technically, they do not do anything wrong- Sans Digital supports that box with Green drives in JBOD mode, as I run them. But that is not the intent of the marketing, and it is no wonder so many people are losing data on Green drives being run as Raid5.

This is just a very long and detailed, and documented as best I can, way of saying that just because any of these boxes are bundled with any particular drive does not mean they are certified to run in any particular configuration.

A few months after the Red drives were introduced I searched the Sans Digital forum (then still alive) for "red" or something like that, and found a single post addressing the issue. The same Sans Digital rep (or some rep using the same user id) said "No, we do not support Red Drives in Raid-5 mode, only enterprise drives". That by memory but I have a very specific recollection on that, and it changed my thinking on Red drives.

And again, check WD's HCL list for the Red drives - no Sans Digital DAS raid boxes, nor any of the other usual suspects. That should tell you something.

Just out of curiosity, I am going to email Sans Digital support and ask them about Red drives on my Raid box. Just to verify their thinking has not changed. But it being a weekend, it may be a few days before I hear back. I'll post their reply here.

I believe I have told this story previously here, related to a discussion about Red or perhaps green drives.

You did not say who you were going to call, but I would certainly like to hear what they have to say!

_____________________________________________________
Drobo S (V1) 2x2TB WD20EARS 1x2TB WDEARX 1x1.5TB WD15EARS 1x1TB WD10EADS
Single Disk Redundancy (for the time being)
WinXP SP3 via USB2.0
Win7 Pro, via Rosewill RC-219 eSata HBA
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01-05-2013, 03:16 PM
Post: #20
RE: Choosing the right drives for my Drobo 5D
I would call Sans Digital to ask why. And yes monday since its the weekend. But clearly they will say no RED's if you are using JBOD but i would ask about RED's being used when in RAID setting.
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