Post Reply 
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Choosing the right drives for my Drobo 5D
01-06-2013, 09:28 PM
Post: #21
RE: Choosing the right drives for my Drobo 5D
theres lots of interesting things mentioned here.

also some handy info here too regarding tler:
http://en.wikipedia.org/wiki/Error_recovery_control
(it's interesting to see that WD removed a tler util which could turn tler on, or off, for a range of their drives - maybe part too much hassle supporting people who used it in the wrong way and had problems, or to prevent people improving their cheaper drives instead of having to buy other/or more expensive ones, like overclocking etc)

i think some systems should go back to basics - if you make something, get involved (if you can) in more related parts, eg:

make the controller able to handle all eventualities
&
make the drive able to handle all eventualities.
&
make any other software work with it too.

(its simple in concept, a lot more complex then it would first seem to be, but not that complex to achieve if there are some set rules to follow)

like:
1) make all controllers with the ability query another drive (drive2), if the 1st drive doenst respond quick enough, and if another drive has the same data.
2) if drive 2 provides the data, pass that data to the program etc that wanted it as per normal.
3) wait to get status from drive 1
4) if drive 1 responds that is busy doing something, wait
5) if drive 1 gives it the data it already got from drive 2, say thanks and ignore it. (or parity check it if needed etc)
6) if drive 1 responds that it cant provide the data, but other data is still accesible, repair that bit of missing data with a frech copy from drive2, and relocate sector etc if that sector has problems
7) if drive 1 is the only source for that data, and drive reports busy, wait
7b) drive 1 should be designed in a way to be able to give basic status reports such as busy, fatal error, etc to the controller in a standard way, maybe ISO standards etc.
7c) drive 1 should be able to provide other data on sectors of the disk if available, while working on EEC / relocating a bad sector, even if slower
8) controller should be intelligent enough to try querying for another piece of data on drive 1 if drive one is busy, and alert drive 1 as possible drive errors and provide detailed logs on what has been going on, BEFORE simply failing a drive (if that would cause a total dataloss etc)
9) all main O/S modules which interact with controllers, and drives, should be written in a way to caters for all of the above, and be mandatory in new versions going forward.
10) input scenarios in a test bed to make sure the logic is correct and maybe run it through a Mathlab or something and maybe that will help simplify potential issues with raids.

the TLER concept of time-limited error recovery, might sounds like a cool feature, but if the controller was able to "control" its own requests to ask another drive anyway, such as "who can give me this data..... "i can/i can" and the 1st drive to provide it provides it, then why impose an actual limit on Error-recovery? - would we want to give an array as much time as possible (in essence) to give us some data if it has a chance of EEC correcting itself and providing it rather than accepting it as lost?

just my thoughts Smile

(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)
Find all posts by this user
Quote this message in a reply
01-07-2013, 08:53 AM
Post: #22
RE: Choosing the right drives for my Drobo 5D
Paul, you are making the mistake of looking at this from an engineering point of view, not a marketing point of view. This is purely a marketing issue.

It is pretty obvious that drive makers are using TLER (or whatever each maker calls it) as an artificial reason to sell higher margin enterprise drives.

Probably 90% of the Raid problems could be solved by changing the time out interval in Raid firmware, which is a couple of keystrokes of work. Or making the time out a user defined variable so Raid arrays could behave either way. But AFAIK no one has done that (with the likely exception of software Raid like Linux MDADM, ZFS, and hopefully Drobo firmware).

That's why I called it a SCAM in my last post. If you look at the big picture, the entire storage market, including the Raid box makers, are all working in concert on this, and in the meantime the box makers and resellers (like NewEgg) add salt to the wound by bundling Green drives with their Raid boxes. Thus encouraging consumers to build arrays destined for almost certain failure.

The most peculiar part of this is that it does not appear to be in the best interests of the Raid external box makers to do that. Yet they do. The motivation escapes me.

_____________________________________________________
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
Find all posts by this user
Quote this message in a reply
01-07-2013, 03:08 PM
Post: #23
RE: Choosing the right drives for my Drobo 5D
TLER is actually easier to implement than non-TLER... With TLER you try a few times and give up! Smile

In terms of marketing, bundling green drives with "consumer" RAID boxes has only one motivation - lower cost of entry.
When selling to the cheap-minded, every penny counts. This is why I see people who have spent good money on fast CPUs, fast hard drives, and good RAID controllers literally cripple the machine with cheap-and-nasty RAM. It's like buying cheap gasoline and retreaded tires for a performance sports car. Sad


Green = consumer use, no TLER so in RAID situations either the controller has to be dumb enough to not "notice" a slow/hung drive, or it has to be smart enough to realize that green drives might appear slow/hung and tolerate that. Geared toward low power and to some degree low noise. Some might argue they're also geared toward failure. Tongue

Red = NAS/RAID use, TLER (of some sort), geared toward quiet, low-heat, 24/7 use.

AV = TLER (I think there's NO ER at all, the assumption likely being that a DVR can lose a few frames and safely blame the cable/satellite company), geared toward quiet, low-heat, 24/7 use. I believe there are buffering optimizations here to allow for simultaneous stream access as well.

Black = Enterprise RAID, TLER, geared toward performance applications, requires good cooling, noise and heat reduction are not the major design goals


For the Reds and "certified" usage - I think it's precisely that - whomever the RAID box vendor is needs to approve its use. Some of them care, some of them couldn't give a hoot. Probably the same applies when they get complaints of "I bought this bundled with Green drives and everything failed" - the ones that care would tell the Neweggs of the world "Look, QUIT doing that or we won't let you sell our products anymore!" and the others either don't care, or believe their products work fine with Green drives.

From the manufacturing end, Black drives need to have the "best" guts.
It seems like it's just a matter of loading the right firmware, and in some cases, if production yield is awesome, it very well may be.
However, production yield usually isn't that awesome, so produced parts likely get tested, then sorted, rather than simply accepted or rejected.

I think of it similar to this write-up on resistor yields...


Prior to WD "fixing" things, back in the day people would enable TLER on the lower-end non-RAID drives for RAID use. I don't know how many of them ran fine versus how many ran into problems, but to me it's like overclocking - if there are larger tolerances (like nettops where they're underclocked for heat and silence), you can "squeeze" more out of it, but if you want to be safe, leave it be.

Meanwhile, manufacturers will "squeeze" more out of us for those larger tolerances. Smile


Long story short, they may not be the same components with different firmwares, though at times they might happen to be, depending on how production yield and market demand (don't) match.

--Brandon | WHS2011+Drive Bender/2x Drobo v2/Drobo S G1/ Drobo S G2/Transporter
Drobo provides fault-tolerance, it's NOT a substitute for regular backups.
Drobo Best Practices - Official and Community-sourced.
Find all posts by this user
Quote this message in a reply
01-07-2013, 04:17 PM (This post was last modified: 01-07-2013 04:30 PM by NeilR.)
Post: #24
RE: Choosing the right drives for my Drobo 5D
Hi Brandon,

AFAIK, WD Black drives DO NOT have TLER ENABLED. They are no different than Green or Blue drives in that regard. My understanding is that only RE and maybe Red drives have TLER enabled. If you think otherwise I'd like to see a credible link.

Sans Digital doesn't just "not care" how the drives are sold; they are complicit in the deception. As I mentioned previously, the most recently available user guide for my TR4UTBPN lists various Green drives in their HCL list but does NOT specify that they are only compatible for JBOD configurations...

Up until a few months ago, the only published info on this was in Sans Digital's support forum, where their reps told people with failed consumer drive arrays that only WD RE drives were certified for Raid use. The only way you, the end user, could determine that was to search the support forums.

Sans Digital has recently killed their support forums. At the present time I can not find any official discussion, whatsoever, on their site informing customers that the official user manual is incorrect in that regard, nor that consumer drives are not recommended and are not supported in any way for Raid.

If I am wrong on that I would like to see a link; my last extensive search found nothing.

That is complicity.

And further, it is highly unlikely that Sans Digital does not actively support NewEgg's bundle deals with rebates and/or discounts. Some of those bundles are so cheap that it is impossible that NewEgg finances the deals through their regular margins.

The same "scam" is going on with Microsoft OEM software. MS says that end users cannot buy OEM software, only "System Builders". But Newegg's regular discounting of OEM software always indicates a quantity 5 limit.

No legitimate systems builder buys OS software in quantities of 5 or less. They are buying by the many dozens or hundreds (small builder) to the thousands. And MS doesn't just "turn a blind eye" but surely funds or shares in the promotional costs of those offerings, as do likely all of Newegg's suppliers share in all of NewEgg's promotions.

It is just a thinly veiled charade engineered to allow MS to wash it's hands of support for $80+ a pop software. Same charade surrounding the marketing of consumer drives to Raid users.

As far as relative quality, I don't think you can divine that even RE drives are any more reliable, simply based on the relative reporting of DOA and early death from user reviews. The most common complaint I see on RE consumer reviews is something like "I paid (2x to 3x) as much and I'm still getting (some high percent) of failures... what am I paying for?".

And regardless of relative quality levels, it is TLER that more or less guarantees an early death to a Raid array, where the relative true MTBF would only change the relatively low probability of "lightning striking". There are other firmware related differences between enterprise and consumer drives but I suspect TLER is the most critical.

I'm not saying enterprise drives, or even Black drives might not have components that are the "pick of the litter", but just suggesting that only marginally changes the end result, where lack of TLER dramatically changes the end result.
Brandon,

Regarding the issue of box makers not being "required" to certify their drives, consider this...

1. If only one DAS Raid box maker certified their box for Reds, that would put all the competing box makers at a severe competitive disadvantage.

2. There are no, zero, none DAS box makers on the list (except Drobo, which is not traditional Raid). *ALL* the NAS box makers are on the list because otherwise... they would be at an untenable marketing disadvantage.

There is something going on here other than "these device makers are not required to certify the product for Reds even if they would work fine". This is simple logic and a simple look at the Big Picture.

_____________________________________________________
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
Find all posts by this user
Quote this message in a reply
01-09-2013, 09:07 AM (This post was last modified: 01-09-2013 09:09 AM by NeilR.)
Post: #25
RE: Choosing the right drives for my Drobo 5D
On Monday I did get a response from Sans Digital about support for Red drives. Their support is unchanged from what I saw on their now defunct support forum - they DO NOT support Red Drives for Raid in their enclosures...

Quote:"Thank for using our product.

WD RED drives are specially designed for NAS application.

If you are going to use JBOD mode, you could consider desktop drives.
If you are going to do RAID configuration, we suggest using RAID/Enterprise edition drives.
"

And as I mentioned previously I am not aware of any DAS enclosure maker that does explicitly support Red or Desktop drives in Ria denclosures although some other box makers are totally silent on the whole issue (as is Sans Digital with the exception of a newly found statement buried in a FAQ titled "Do your units support the latest 2TB SATA II hard drives?").

_____________________________________________________
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
Find all posts by this user
Quote this message in a reply
01-09-2013, 03:29 PM
Post: #26
RE: Choosing the right drives for my Drobo 5D
I had this (not so) great long-winded response all ready but the system banned me, LOL.

NeilR, you are correct, my mistake. Blacks do *NOT* have TLER - they're just fast and hot. I got RE and Black confused.

Please don't take this as me being argumentative, just playing devil's advocate as I work for a technology manufacturer, so just providing my experience from "the dark side" of marketing. Wink

My search found these two Sans Digital product pages
http://www.sansdigital.com/towerraid-plus/tr8mp.html
http://www.sansdigital.com/eliteraid/er104utplusb.html
that note:
Quote:Note: Sans Digital recommends the use of enterprise hard drives when in use with any RAID controller applications. Standard desktop or green desktop drive may not be supported and may compromise RAID system stability and performance.
"may not be supported" hmmm fuzzy. Equally as fuzzy as your support response of "suggest" and "could consider" - very non-committal, heh.


Unfortunately in my experience (and I hope it's not true everywhere), often the "carrot on a stick" of sales revenue trumps support and marketing. "Hey, let us do this (very unwise) thing and we'll buy TONS of your product" gets chosen over satisfied customers and less support impact. Companies don't often think things all the way through, and when the support volume upticks, it's someone else's fault - or even the fault of the few that spoke up. (Yeah, I'm a tad bitter today...)

On RE vs Black, I honestly don't know what more you're not getting (in an RE), versus what less you're not paying for (in a Black), especially since the warranties are the same. So yes, could very well simply be charging what the market will bear. Still tons of people (and government agencies) willing to pay extra premium for some inkling (real or not) of a guarantee or support.

DAS-wise, the only thing I found was the IcyBox IB-NAS5520-B from WD's list that claims to support both DAS and NAS functionality, but it's an exception in the family, it seems.

Red drives are an odd gamble for WD, it seems. At least the AV drives have a committed DVR market. Remains to be seen what market share the Red drives will hold. I just hope they don't start making an entire rainbow of drives, that would hurt.

--Brandon | WHS2011+Drive Bender/2x Drobo v2/Drobo S G1/ Drobo S G2/Transporter
Drobo provides fault-tolerance, it's NOT a substitute for regular backups.
Drobo Best Practices - Official and Community-sourced.
Find all posts by this user
Quote this message in a reply
01-09-2013, 04:28 PM (This post was last modified: 01-09-2013 04:58 PM by NeilR.)
Post: #27
RE: Choosing the right drives for my Drobo 5D
Good to see you back from the Dark Side, Brandon :-)

I do not consider you argumentative in the least, and certainly not more argumentative than I have been :-). This is just an honest and open discussion of differences in perspective. I don't think we have any disagreement on the facts, just perspective.

I see you agreeing with me, 100%, that these products are marketed "dishonestly", to the extent that marketing controls what goes into the all the marketing romance text, not engineering. Where we differ is in how you rationalize the process. I can't do that. Yes, I acknowledge intense pressures to sell product but I do not see that as a legitimate excuse to "lie" and "deceive".

I also think it is a "dangerous" rationalization because ALL businesses face intense marketing pressure. The same logic would excuse any bad behavior of any business. In the end it is an attempt to make the unethical quite ethical or at least somehow "necessary".

And it is deception, not carelessness. These issues are totally understood by the makers, and they know full well the implications. Even the marketing people. Their support staff knows EXACTLY how many Raid arrays blow up every year due to use of the wrong drives, they just don't publicize it.

The IcyDock device is interesting, but it is not truly DAS. The initial formatting of the drives MUST be done while connected via NAS, and that is stressed in numerous places in the manual.

The end result, I guess, is a Linux file system that is directly accessible via USB, presumably by some "magical" device mapping of that network share to a Win drive letter. Or something similar.

But the point is that the Raid arrays in that box are most likely Linux MDADM arrays, just like the other NAS box.

Of the two Sans Digital devices for which you found references to drive recommendations, one is a rack mount sold mainly to enterprises, not consumers. How many consumers buy rack mount servers and disk enclosures?

The other is an 8 bay box, not one of their top sellers. Their top sellers are the 4-5 bay boxes typically promoted by NewEgg and others.

Call me cynical if you will, but I am noting here that the most popular devices do NOT include that HCL advice, and I personally have never gone through all their products looking for exceptions. Nor do most other end users; they just look at the device(s) they are interested in.

I'll continue my cycnicism... your argument is along the lines their attorneys would use if faced with a class action suit on this. Or more along the lines that, hey, these are just a bunch of frat brothers and they are too busy getting stoned and selling product to get all the details right.

As I said, I just don't see it that way- I don't allow any quarter on that. I know an intentional scam laced with the thinnest possible veneer of faux legitimacy when I see it.

(I actually think this would make a great class action suit. It would be trivial to find hundreds of victims of failed consumer drive arrays, and the reseller bundling really makes it even more interesting.)

And again, I am not trying to be argumentative or rude; just explaining my perspective on this.
PS... WD should own the NAS hard drive market now. I don't see how that can't be a great coup for WD.

Plus they will pick up a lot of business from end users who (arguably very wrongly) use them in DAS arrays, not understanding the somewhat fine distinction and lack of actual "blessings" by their DAS makers, who don't even own up to to the consumer drive problem (as we have discussed in great length).

I'm even thinking about putting 5x3TB Reds in my Drobo S. The more I think about it the more it makes sense. The ~$850 cost is not very exciting though, especially since I can live without them for awhile, which I probably will.
P.P.S ... You noted this rather wimpy disclaimer in those two Sans Digital marking pages with the "may"s...

Code:
"Standard desktop or green desktop drive may not be supported and may compromise RAID system stability and performance."

I can tell you for a fact, easily verified back when Sans Digital had a public support forum, that if you reported any problem with Raid integrity whatsoever, and also reported using desktop drives, you got one and only one unambiguous answer - "we do not support the use of desktop drives in our Raid configurations. We only support Enterprise drives".

And you got no further support or suggestions from the Sans Digital forum rep. I saw this in literally dozens of threads.

You can no longer verify that, and why I mention it.

_____________________________________________________
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
Find all posts by this user
Quote this message in a reply
01-09-2013, 05:39 PM
Post: #28
RE: Choosing the right drives for my Drobo 5D
I think you're on to something with class action - even with the changes to make it more difficult to file class action suits, I think the point could be made that offending manufacturer(s) knowingly allowed "doomed to failure" configurations to proliferate into the market. It's being knowingly negligent, and being knowingly negligent should define enough intent.
So I agree with you on the dishonesty of the situation.

For me it comes down to the argument we often provide to users who come here with "Drobo marked my drive bad but it's perfectly fine for other things" ... You've spent all this money and effort to protect your data, why risk it?

WD should take that as a marketing point!!
"You bought a fast NAS. You bought a safe NAS. Why risk it all with cheap drives?"

--Brandon | WHS2011+Drive Bender/2x Drobo v2/Drobo S G1/ Drobo S G2/Transporter
Drobo provides fault-tolerance, it's NOT a substitute for regular backups.
Drobo Best Practices - Official and Community-sourced.
Find all posts by this user
Quote this message in a reply
01-09-2013, 06:04 PM
Post: #29
RE: Choosing the right drives for my Drobo 5D
(01-09-2013 05:39 PM)bhiga Wrote:  For me it comes down to the argument we often provide to users who come here with "Drobo marked my drive bad but it's perfectly fine for other things" ... You've spent all this money and effort to protect your data, why risk it?

I was thinking about that today... I don't recall seeing a lot of comments about Drobo "marking drives bad that test ok" in the recent past here. I was idly wondering if there might have been firmware tweaks in that regard. One of those True Mysteries. I've never actually had a drive fail in a Drobo. I'm like a skydiver that has never needed or deployed his reserve and therefore has no idea if it really works in the real world :-)

Not that I am complaining about my track record :-). All with various 1, 1.5 and 2TB WD Green drives.

I did have one drive badly slowing my Drobo V2 down (1.5TB GP). Drobo support told me to remove it and perhaps use it for something else. It's been running 24/7 since then (1-2 years or more) with no smart errors. I don't count that as a "failed" drive since it was not actually rejected by the Drobo and always functioned, if rather slowly at times.

I got a response from Sans Digital to a follow up question:

Code:
Thank you for your response.  Can you provide any details as to exactly *WHY* Red drives are not certified for your Raid enclosures?  

It is my understanding that Red drives support TLER and it is the lack of TLER in “desktop/consumer” drives that is the reason why they are not certified for Raid use.


And their reply:

Code:
"If you check the link below, you could see more information about WD RED drives. http://www.wdc.com/en/products/products.aspx?id=810
As I mentioned, according to Western Digital, they design RED drives especially for NAS environment.

Therefore, we don’t test/use it with our DAS (Derict-Attached-Storage) models. You still could use RED drive in non-NAS enclosures.
However, if there is any issue happens, it will be hard to get any support from WD."

I found that reply no more insightful than anything I could come up with on my own :-)

_____________________________________________________
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
Find all posts by this user
Quote this message in a reply
01-09-2013, 06:08 PM
Post: #30
RE: Choosing the right drives for my Drobo 5D
LOL!! The natural question is "So what's different architecture-wise between your NAS and DAS enclosures?"

But I wouldn't hold my breath for an "un-canned" answer. Wink

--Brandon | WHS2011+Drive Bender/2x Drobo v2/Drobo S G1/ Drobo S G2/Transporter
Drobo provides fault-tolerance, it's NOT a substitute for regular backups.
Drobo Best Practices - Official and Community-sourced.
Find all posts by this user
Quote this message in a reply
Post Reply 


Forum Jump: