Brian

Seagate Barracuda Green 2TB Review

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Ok, some of the reading in what I listed above seem off as to what we expected. The part about the offset being 0 on all of them and the both generation of greens being 512/512 is really strange. Any ideas which linux kernels fully supported proper recognition of newer 4K drives?

The recognition itself is correct. But WD idiots crippled drives to lie about physical sector size. Pre-production drives reported 512B logical and 4kB physical. But the production drives hit the market with curiously crippled firmware reporting wrong values. The worst thing is, this is not a bug, but the feature.

Here is the kernel developer commentary:

First of all it's important to distinguish between logical block size which is used when sending commands to a device and the physical block size which is used by the device internally.

Linux has supported (SCSI) drives that present 4KB logical block sizes for a long time. For compatiblity with legacy OS'es, however, consumer grade ATA drives with 4KB physical blocks continue to present a 512-byte logical block interface. The knob indicating that the drive has 4KB physical blocks is orthogonal to the logical block size reporting, allowing the information to be communicated without interfering with legacy OS'es like XP that only know about 512-byte sectors.

We have worked closely with disk manufacturers for a long time to make sure we were ready. Western Digital have been instrumental in the ATA specification in terms of the alignment and physical block size parameters. The engineering sample drives I have received from WDC have all implemented the physical block size knobs correctly. Which makes it even more baffling that they end up shipping an advanced format drive that gets it wrong. I have no idea why they did that. The location of the block size information in IDENTIFY DEVICE is unlikely to be inspected by legacy systems, so I highly doubt it's a compatibility thing. Brown paper bag time for Western Digital...

It is true that the effects of this particular drive reporting incorrect information could have been mitigated by a 1MB default alignment. However, that would still have caused misalignment for other drives that come wired with 1-alignment to compensate for the legacy DOS sector 63 offset. So blindly aligning to 1MB won't cut it. Windows Vista/7 don't do that either. Like Linux, they compensate based upon what the drive reports.

Linux 2.6.31 and beyond will report device alignment and physical block size for all block devices. It is then up to the userland partitioning utilities etc. to adjust start offsets accordingly. You'll find that both parted and util-linux-ng have been updated to do this. And that modern fdisk will in fact align on a 1MB (+/- drive alignment) boundary by default.

Caveat being that Fedora is the only community distribution I know of that's using the updated bits. I don't think all of them made it into Fedora 12 but I'm sure Fedora 13 will do the right thing.

So I encourage you to work with your distribution vendor to ensure they start shipping recent partition tooling.

Martin K. Petersen

Kernel Developer, Oracle Linux Engineering

Edited by StorageTux

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Let me ping our WDC engineering contact... apparently it had come up that there are two types of drives shipping. Consumer channel and other, which one might be force emulation, the other might work like the early production models did. It would be nice to get a solid answer on which ones these are we have in for testing and where certain drives might show up. If its something like "models in OEM computers are X and models you buy from BestBuy/Newegg/Etc are Y" that would be nice. If it turns out that retail boxed models are different from OEM/bare drives... then we have a big problem.

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Are the drives on QNAP's list of qualified drives? If this is for home use, you might chance it either way, but with Seagate exiting the green drive space, I wouldn't use them even if qualified for business use.

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Are the drives on QNAP's list of qualified drives? If this is for home use, you might chance it either way, but with Seagate exiting the green drive space, I wouldn't use them even if qualified for business use.

I don't have the QNAP but I am running about 120 of these drives now in a raid. Frankly, don't get them if you have a choice instead you may want to look at the SV35 series which are rated for 24x7 use unlike the 6-hours a day use for the 'green' ones. Main problems I've seen: Long error recovery periods both during initial spin-up as well as in operation (no means to enable TLER); Less compatibility with backplanes/controllers (LSI; areca (which use an LSI expander chip) and the older Vitesse chipsets, basically errors such as "log_info(0x31120303): originator(PL), code(0x12), sub_code(0x0303)" which are messages from the drives. I think they're on the ragged edge and not really designed for much more than a tertiary drive for /very/ light use.

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I don't have the QNAP but I am running about 120 of these drives now in a raid. Frankly, don't get them if you have a choice instead you may want to look at the SV35 series which are rated for 24x7 use unlike the 6-hours a day use for the 'green' ones. Main problems I've seen: Long error recovery periods both during initial spin-up as well as in operation (no means to enable TLER); Less compatibility with backplanes/controllers (LSI; areca (which use an LSI expander chip) and the older Vitesse chipsets, basically errors such as "log_info(0x31120303): originator(PL), code(0x12), sub_code(0x0303)" which are messages from the drives. I think they're on the ragged edge and not really designed for much more than a tertiary drive for /very/ light use.

Do you mean these? They are quite more expensive and I don't need them to run 24h anyways.

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yes, they are more expensive but:

1) they are still sold/supported and have a 5-year warranty opposed to 3 year.

2) designed for 24x7 (8760 hours/year) use opposed to ~6hours/day (2100 hours/year)

3) since they were speced for raid systems should be more robust in firmware support to avoid dropping out or causing errors like I'm seeing with all the ST2000DL003's.

Having been 'wooed' (and yes, I /SHOULD/ know better as I do this all the friggen time) by the lower price of the ST2000DL003's, they are not worth it IMHO. I've had to replace about 20 of them so far due to hanging the bus or other similar 'soft' errors which is way more than the hitachi's or the better seagate drives. (been burned too often by WD in the past that I don't even try them anymore). Likewise though your mileage may vary. Just so you're aware and it may/may not affect your roll of the dice.

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Having been 'wooed' by the lower price of the ST2000DL003's, they are not worth it IMHO. I've had to replace about 20 of them so far due to hanging the bus or other similar 'soft' errors which is way more than the hitachi's or the better seagate drives.

Just in case anyone is considering buying the ST2000DL003 I have to also warn against it: "hanging the bus"; that sounds exactly like what I'm getting: all of a sudden the disk stops responding, Linux resets the bus a few times and then gives up. After a reboot all is fine, no bad sectors are to be found anywhere. This seems to mostly happen when there is too much I/O, more specifically maybe mostly when there's a mix of sequential and random I/O.

Seagate has not updated the firmware once since January 2012, and support does not care about the issue: they say one should not use the drive in a server (my desktop); that it should not be run 24/7, that it's not meant to be used in RAID (Linux software RAID1), etc. Way to stand behind their product!

The only usage for which this drive may be suited is for storing one's video or music collection. That should not generate so much I/O as to overwhelm the drive. Otherwise, to mitigate the issue I recommend only using the disk in RAID so that when the drive 'freezes' it does not crash the computer; and, if using Linux's software RAID, to use write-intent bitmaps to speed up resync ('mdadm --grow --bitmap=internal /dev/md0' re-add the disk with 'mdadm /dev/md0 --re-add /dev/sdb1').

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The only usage for which this drive may be suited is for storing one's video or music collection.

All hard drives experience high I/O loads during backup. And using hard drives without backup is a waste of time. I've got have half a dozen ST2000DL003 in 2011 and one already failed. I use these drives mainly for backup, they're reasonably fast.

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