WD Green drives in an Areca RAID

[Alex Gerulaitis]

[Chris Murphy] “WDC explicitly proscribes the use of Green, Blue, and Black drives in anything other than raid1 or raid0. The Red’s are proscribed in arrays comprised of more than 4 disks. The RE’s are recommended for 5+ drive arrays.”

..and I thought WDC “proscribes” this (and cripples the firmware on Greens, Blues and Blacks) primarily because they want to sell pricier models, not because there is some other scientifically sound reason to? 🙂

Is Red anything but a Green with a slightly modified firmware that somehow costs $50 extra to the end user?

[Chris Murphy]

Newegg.com
WDC Red 2TB = $119
WDC Green 2TB =$109

WDC Red 3TB = $150
WDC Green 3TB =$128

It’s $10 and $22 respectively. Most people are going to save a couple hundred bucks. At least Murray has “saved” in the realm of $2k-5k, but I think they’re going to end up being more hassle than they’re worth.

But if you look at the specs, they match up very much the same, although the power consumption and acoustics are slightly different and I doubt that comes from firmware alone. If they are identical, WDC could be sorting them based on test performance data after assembly, before labeling and setting a key in firmware that makes the drive behave according to its model. So it might even be the same firmware. The real question is, why does it matter?

Back in the late 90’s I consulted with a TV station about to supplement their quantel’s with a Mac based video editing station. I can’t for the life of me remember the company/brand, but what I do remember is the various products were in fact a single software and hardware base, with feature sets unlocked by firmware in the hardware card and a serial number (or possibly a dongle) for the software. The difference in price was in the realm of $5000 for the low end and $30,000 for what the customer ended up buying. Same hardware and software installed, enabled by firmware and a code.

Today I work primarily in color management and the same thing is common, you get identical hardware, but features are unlocked depending on what you paid for, all of it being dongle protected.

And this was extended several years ago to CPUs. Intel disables some of the cache and the cores and sells those chips as a different brand (Core i7) than the ones with all cores and cache enabled (Xeon). You get what you paid for.

So I don’t see why it matters. You want to save $10-50 and get the exact wrong firmware behavior? Good luck with that, but I don’t see it as sticking it to the man when you make that choice, you’re sticking it to yourself.

[Alex Gerulaitis]

[Chris Murphy] “You want to save $10-50 and get the exact wrong firmware behavior? Good luck with that, but I don’t see it as sticking it to the man when you make that choice, you’re sticking it to yourself.”

Sticking it to the man doesn’t mean shooting yourself in the foot. I never used Green drives in RAID and don’t plan to.

Sticking it to the man means you have to be smart about it and mitigate the adverse affects of using eco drives – smartly, not stupidly. All I said was – there’re ways to do it. Did you read my post? 🙂

[Chris Murphy]

Yes, there are also smart ways to use a pistachio shell as a water filter.

So you aren’t using or recommending Green’s, and yet in the previous post your two questions insinuate that either the difference in firmware behavior is unimportant/meaningless, or that somehow WDC is acting immorally by charging more for different firmware behavior. And you’re also discounting the 3 year versus 2 year warranty, and the fact that the Green’s 2 year warranty is technically invalid per the marketing spec sheet if you use it in raid. So it’s a three year versus 0 year warranty, for a $22 difference. And you think this is sticking it to the man. Yes I have read your post and the point escapes me, other than something in between “ill advised” and “rather tedious to mitigate”, can still be done. Actually the pistachio shell as a water filter makes vastly more sense, at least it’s compostable.

Meanwhile I’m informed off-list that bin sorting is not used for mechanical drives. So it seems more likely there is in fact a physical difference between Green and Red models, no matter how similar they look from the outside or on paper. Obviously WDC trusts the Reds for an additional year of usage on top of the fact it’s qualified for 24×7 use and the Green is not.

[Alex Gerulaitis]

[Chris Murphy] “yet in the previous post your two questions insinuate that either the difference in firmware behavior is unimportant/meaningless, or that somehow WDC is acting immorally by charging more for different firmware behavior”

Point: green drives can be used where the difference in their behavior (with reds or other similar drives) is either irrelevant or well mitigated. Didn’t I say it three or four times already? If it still escapes you, perhaps contact me off list?

At price differences you mentioned – no point. When the price difference were to the tune of 30-50% (I think a year ago or so) – there clearly is a point.

Oh, and the fact that using green drives wasn’t the culprit in OP’s issue: did that point escape you too, or are you still out to make compostable water filters?

[Chris Murphy]

USB stick RAID can be used where differences in their behavior is either irrelevant or well mitigated.

If you have a mitigation example for using Green drives in raid, that might be a useful qualification.

Even at a 50% premium for Red vs Green, the Green’s warranty is invalidated by using it in any raid, so is that really worth 1/2 off, in addition to having the wrong ERC timeout?

Yes I did notice the OPs problem wasn’t related to the use of Green drives, because his thread update was in reply to my belated comment, in which I didn’t focus on Green drives being the culprit.

[Alex Gerulaitis]

[Chris Murphy] “If you have a mitigation example for using Green drives in raid, that might be a useful qualification.”

MSS, RAIDZ, Linux RAID(6), Drobo BeyondRAID. I believe big cloud players use similar schemes (perhaps geographically distributed and with triple redundancy) that are would well mitigate the use of green drives – if they don’t already. I do know they use desktop drives – which of course invalidates their warranty, right?

[Chris Murphy] “USB stick RAID can be used where differences in their behavior is either irrelevant or well mitigated.”

First compostable water filters, now USB sticks. I take it, you’re trying to make the idea of using green drives in RAID sound outlandish? 🙂

You do have a point about potentially invalidating drives’ warranty and about the difference in cost being too minor. That changes nothing about mine.

Cheers.

[Chris Murphy]

I can’t speak to MSS, but I can the other three. None by themselves mitigate the consequences of the WDC Green’s high SCT ERC timeout. RAIDZ can of course detect errors that the drive cannot, but before ZFS (or Btrfs or ReFS) kick in with their own ECC, the drive ECC is in charge. When it encounters a problem, it will attempt error recovery itself for up to 2 minutes before it sends the data to the controller. If you’re lucky, the drive errors out much sooner and ZFS can then correct for that, as can the linux md driver. But likewise, the md driver can’t work around the high time out either. It simply must wait. The linux SCSI layer by default has a lower timeout than these drives (as do many hardware raid controllers), so if the SCSI layer timeout is reached before the drive timeout, the drive is reset. The drive then can’t report a read error or what sector was experiencing a problem to the kernel, and thus it isn’t fixed by either RAIDZ or the md driver.

With some luck, the drive errors out sooner, and then either ZFS or the md driver will receive the read error from the drive which includes the sector LBA, and the data can be reconstructed from parity, handed off upstream to your application and downstream back to the drive to overwrite the bad sector. This is far less certain and common when the drive has high ERC timeouts though. And that timeout isn’t configurable on the Green. Regular scrubs are likewise adversely impacted by the high ERC timeout of the drive. The timeout is critical to getting the correct data for the bad sector and causing it to be overwritten.

As for Drobo, well, I think it’s weird they’d want to support something that WDC themselves do not. And after Scott Kelby Drobo Experience, I wouldn’t trust it for photos let alone video I cared about, regardless of the drive it uses.

Now, I’ll grant that using a Green drive in raid can be done, and can work, but with such huge PITA caveats that it’s just not worth it in the likely context of this forum. Google, Amazon, I don’t know if they use these drives, but they do use consumer drives for certain use cases, I wouldn’t be surprised if they get a great deal for a DOA only warranty. But they also use distributed file systems. So they can lose not just a whole array, not just a whole rack of storage, but an entire data center, and keep plugging along. They don’t use distributed file systems to mitigate using cheapo drives. They use cheapo drives in some cases because they have a distributed file system in place for many reasons other than storage failure mitigation. And when Google have problems with this system the delays aren’t just a few seconds, so I’m skeptical if it’s adequate enough for the demands of video work.

A mere mortal could pre-emptively mitigate bad sectors by periodically zeroing (or writing anything, or even faster would be to use ATA Security Erase) the drive which will force the firmware to remove any sectors with persistent write failures; and also doing a weekly SMART extended offline test using smartmontools. Both probably qualify as PITA for most people. And then, moving data around to free up drives for their regular wiping, there’s the increased risk getting hit with silent data corruption.

So yes, USB stick raid is probably more ridiculous than using Green drives in raid. But compostable pistachio shell water filters are a better idea.

[Steve Wang]

Hi,

Bring thread from the dead =)… I just wanted to add a few things related to WD Green drives and Areca 1880 cards.

I’ve been using and areca 1880i with 5 x 2TB green drives RAID5. I got them a couple years back when they had 3 year warranty. Started with 4 drives and migrated to 5 drives few months back(long story but needed drives for other purposes). Monthly scrubs. Drive is constantly accessed, so it rarely “parks”.