D-Link Forums
The Graveyard - Products No Longer Supported => D-Link Storage => DNS-321 => Topic started by: kstrait on May 18, 2010, 10:20:17 AM
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I have found some discussions and guides on how to make the DNS-323 work with the WD20EARS drives but cannot find anything for the DNS-321. Is there a way to make these drives compatible? If I put these drives in will I be able to format them at all and use them with a hit on performance or will they just not work at all?
Any help you can provide would be greatly appreciated.
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Have you tried the procedures outlined for the DNS-323?
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No I have not. I haven't purchased the drives yet as I want to be sure I can make them work with the NAS before doing so. I would just get the EADS but the EARS are much cheaper now as there are plenty of good deals on them.
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I'd buy drives known to be compatible, but that's just me. :)
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Right. What I am trying to find out is if the WD20EARS are compatable....find someone who has them working in a DNS-321. :)
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Even if someone "has them working", there's no assurance that they're getting full performance or they won't experience issues they're not seeing yet.
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Even if someone "has them working", there's no assurance that they're getting full performance or they won't experience issues they're not seeing yet.
I can't understand why ? I also can't understand the reason about "we aren't going to support the drives" sticky as well.
If its about the advanced format (i.e. 4k sector size) then its well known that the need for reallignment only applies for pre Vista windows OSes. Vista, Win 7, Mac and Linux is not affected by the 4k sector size. DNS-323/321 is running a linux underneath that web interface. Why would this linux distro be affected by the 4k sector size ?!?
I am also not sure why there should be a special procedure to get the EARS drives running inside a DNS-321, I have a 1.5TB EARS and 1.5 EADS and I can confirm that both were formatted without any issues (FW 1.03) and both are running (individually) at similar performance levels, as matter of fact EARS is performing a little better in the DNS-321 than the EADS.
I would appreciate any enlightenment about this issue.. aside from the WD desktop drives well known issues with RAID controllers because that doesn't apply if the drive is used in a non RAID mode.
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That is exactly what I was expecting to hear from someon, that the EARS would work just fine as long as RAID was not being used. Thanks aasoror.
Has anyone tried this with the 2TB EARS drive?
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Well I didn't know any better because I bought everything before I found the sticky, but yesterday I put two WD20EARS in RAID 1 configuration on my DNS-321. I haven't done any benchmarking but everything seems to be functional.
I'm not real up on file systems and drive architecture but the gist that I got from various threads is the physical sectors not lining up with the file system doohickeys is suboptimal. I don't think it's a functional problem, I think it's a performance problem. But maybe I'm wrong... if I were right, I don't understand how RAID could affect things negatively.
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I'm not real up on file systems and drive architecture but the gist that I got from various threads is the physical sectors not lining up with the file system doohickeys is suboptimal. I don't think it's a functional problem, I think it's a performance problem. But maybe I'm wrong... if I were right, I don't understand how RAID could affect things negatively.
The new sector size issue has nothing to do with RAID, new sector size only affects pre vista windows system (that requires the disc to be re-alligned before proper usage), and that has nothing to do with the DNS-321.
The real problem is between RAID and all the WD-Desktop drives (not only EARS), in a nutshell, WD-Desktop drives will enter what they call "deep recovery mode" upon a failure to read a given sector, this process (similar to a scandisk) will try to recover whatever data on that sector and will mark the sector bad and move the data to someplace else. This recovery procedure might take up to 2 minutes to which the disk will appear unresponsive to the outside world.
Now for RAID side, the RAID controller inside the NAS (be its DNS-321 or any other), as per the RAID operation a disk is deemed unresponsive if it fails to communicate for 7~10 seconds, unresponsive disks are dropped from the disk array (which are typically more than two).
So the problem as can be seen clearly, any WD-Desktop disk that enters a deep recovery mode while inside a NAS with RAID enabled, will be incorrectly considered a failure and will be dropped out of the RAID array. This is not a correct behavior especially if the data can be accessed from other disk (its RAID), the disk doesn't need to attempt to recover the data but the disk has no idea its running in a RAID array, the RAID controller shouldn't drop the disk because its still functional .. but the RAID controller has no idea that the disk is still running. end result is a very unstable (yet functional) NAS.
Check forums.dlink.com/index.php?topic=12483.0 (http://forums.dlink.com/index.php?topic=12483.0) for problem that was caused due this very same issue (not sure why didn't anyone in the thread point to the reason though).
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Very helpful, thanks! So I guess I just need to avoid using WD drives in RAID which is ok by me.
When you went to use your EARS drive, did you have to use a jumper on the drive to set the right offset or did you have to format your drive outside of the NAS? Or did you simply just put it in the DNS-321, format it and it's worked from there?
Thanks again.
Keith
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How often does this deep recovery kick in? I maybe don't mind one drive being dropped and having to be rebuilt once in a very long while. But I certainly don't want to do that once a month.
What happens if one drive is dropped and then another goes into deep recovery?
Gah... looks like I need to return these drives or use them for something else. Too bad we can't just up the timeout on the RAID controller. Is that thing configurable at all on a ffp-enabled box? What kind of controller is it?
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When you went to use your EARS drive, did you have to use a jumper on the drive to set the right offset or did you have to format your drive outside of the NAS?
Not at all, the DNS-321 is running linux which is natively compatible with the 4k sector size.
Or did you simply just put it in the DNS-321, format it and it's worked from there?
Exactly. :)
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I have two green WD 2Tb drives setup in Raid0 - not been a problem for me.
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Yeah but what is the model number of them? WD20EARS or WD20EADS?
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I have two green WD 2Tb drives setup in Raid0 - not been a problem for me.
There wont be a problem in any RAID setup, until one of them goes into "deep recovery" (for whatever reason), the synchronization procedure needed will take several hours (and that's for every single time one of the drives goes into "deep recovery").
Its very risky for those using RAID0, because if a RAID0 drive fails there is no synchronization done and data is lost for good (because its stripped), that said, the drive didn't actually fail, whether the RAID controller will realize that fact after the drive is back from deep recovery (and the NAS is restarted) is something I am not sure any of us is willing to test. :)
Reports here indicate that the NAS is unable to re-detect the drive as a part of the NAS array, but rather consider it a new addition to the array (once the NAS is restarted), this is not problem in RAID1, because the drive can be synchronized (from the other drive), but in RAID0 the drive can't be synchronized.
Unless of course, your aren't using WD desktop drives but the WD Enterprise ones (which doesn't have deep recovery feature).
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Western Digital Caviar Green WD20EADS 2TB 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive.
Sorry does not apply.
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My understanding is the WD20EADS, along with all other current WD desktop drives, has the deep recovery feature.
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My understanding is the WD20EADS, along with all other current WD desktop drives, has the deep recovery feature.
True