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[desau13]

Hi all,

I'm running a DNS-343 with 4 1-TB Samsung HD103SI drives, in RAID-5.  Other than being fairly slow to write to, this system has been running nicely for several years.  (yay!)

Yesterday I noticed that one of the drives is failing the SMART check, the other 3 show no problems.  When I run a quick SMART check, it shows "Fail" (the other 3 show "Pass").  If I run an extended SMART check, it shows "Abort".

Again, these drives have been in operation for several years, so it's probably about time for failures to start.. I've been very satisfied with the longevity of the drives.

So .. I'm thinking of replacing all 4 drives.  While I'm at it, I was thinking of upping the storage to 2TB drives. 

What's my best option for upgrading?

Can I pull out 1 drive (the bad one) and plug in 1 new 2TB drive, then resync, then keep doing that until all drives are replaced?  If I do that, will I get 6GB total? (4x2TB RAID5)

If that doesn't work, then is my only option to pull out the 4 1TB drives and hook them up to some other system in the same RAID configuration to pull off the data, transferring it to the new 2TB drives in the DNS-343?

Thanks!

[JavaLawyer]

Unfortunately, the DNS-343 does not support upgrading an existing RAID-5 array from 4TB to 8TB. You must create a new RAID-5 array from scratch using four 2TB HDDs. Also, do you have a backup of your data? RAID-5 provides redundancy, but is not considered a backup. Even with a healthy RAID-5 array, you should maintain a separate physical backup of your important data.

If you are planning to upgrade your DNS-343 with new HDDs, I recommend installing firmware v1.05 to ensure compatibility with advanced format (AFT) HDDs. Based on member posts on these boards, even with AFT support, RAID-5 has proven problematic with some newer HDDs. Although I can't recommend a specific HDD make/model to use, I do suggest reading these boards to see what other DNS-343 owners used successfully.

Here are a couple of posts from our FAQ board to provide additional information:

• DNS ShareCenter - RAID Resizing
  
• DNS ShareCenter - Total Usable Storage Space
  
• DNS-343/345 - RAID-5 is NOT a Backup
  
• DNS-343 - HDD Size & AFT Support
  

[desau13]

OK - thanks, that answers a lot of my questions.  I'll need to see if I can find compatible 2TB drives.  I did see the compatibility list, unfortunately all of those 2TB drives are EOL'd (that's a 2011 list).  Also, I saw the warning post about Western Digital 2TB drives, so I'll steer clear of those .. looks like I'll be looking at Seagate drives, or perhaps Hitachi.  Is there any recommendation on which brands are higher quality?

Is there a way to pull out the existing 1TB disks and hook them up to a PC so I can read from them to transfer over the data to the new 2TB drives?

[JavaLawyer]

I am personally partial to Seagate, but am unable to recommend specific models that will work with RAID-5. My two DNS-343 are filled with 8 2TB HDDs configured as standard volumes, which mitigates compatibility issues.

Although there is software available that will enable you (theoretically) to mount your RAID-5 array in a PC (you'll have to find a PC with four empty HDD slots as the RAID-5 array must be mounted in its entirety to read), I strongly recommend copying your data manually from the DNS-343 to a secondary storage location.

Again, do you have a backup of your data? RAID-5 does not provide any data security other than redundancy and high availability.

[desau13]

No - I don't have any other backup solution for this data.  I realize this isn't a solid backup solution, and I'm OK with that.  The data here is all multimedia, which I don't deem to be necessary enough to be backed up.  Obviously for the sort of data that I do, I have a separate backup solution.

I'm using RAID5 because it does give me redundancy, which is all I wanted .. so if a single disk goes out (as I'm probably beginning to experience), I can replace it and I don't lose any data.

I can find a system that'll take 4 drives, but I'd need to know how to mount them.

[JavaLawyer]

I cannot attest to the reliability of the software products mentioned in the following thread: DNS-343 - Data Recovery (Windows PCs). If you want to be safe, I recommend copying the data to a PC manually, which may take a couple of days, but isn't that worth ensuring your RAID-5 volume isn't inadvertently damaged during the data migration?

[desau13]

I found enough space on another system to copy over all of my data, then install 4 new 2TB hard drives.  I went with a Seagate 2TB drive.

I installed them, then powered on the system and did a full rebuild using RAID-5.  However, I think when I did, one of the drives wasn't seated all the way, and it only found 4 drives.  Also, another drive was failing the SMART test.  The unit showed it was running degraded, and only showed a total of 6 TB space (only 3 drives were showing, and one of those 3 showed "Fail" for the quick SMART test).

I shut the system down, re-seated the missing drive and started it back up. 

It then showed 4 drives.  I then ran another quick SMART test, which then showed all drives as Pass.

However, it still shows a total of 6TB space, and it shows that it's re-syncing.  I'd be content to let it do so, but it's currently showing me this:
"The Volume_1 is synchronizing now. Please wait for 4631.3min."

I'm not content to wait 77 hours for it to resync _nothing_.  There's nothing on these drives, they're empty / new drives.  Moreover, when I reload that page, it seems to just generate a random number of minutes remaining .. it fluctuates between 1000 and 8000 .. any random number between.

So .. is there a way I can just abort this re-sync and completely re-create the RAID array?

Thanks again!

[desau13]

well .. there you have it:
http://forums.dlink.com/index.php?topic=47484.0

I have the same disks. 

So .. even though the 1.4 firmware "supports 2TB disks", it seems like most of them don't work.

Any advice other than just going back to Frys and keep changing disks until I find some that work?

[JavaLawyer]

. . . Also, another drive was failing the SMART test.  The unit showed it was running degraded, and only showed a total of 6 TB space. . .

Regarding your statement that the RAID-5 array "only showed a total of 6 TB space", a RAID-5 array with 4 2TB HDDs (8 TB space) will allocate approximately 25% of the available space for redundancy, leaving 6 TB of usable storage. The value of 6TB is correct.

DNS ShareCenter - Total Usable Storage Space

So .. even though the 1.4 firmware "supports 2TB disks", it seems like most of them don't work.

Firmware version 1.03 was the first version to support 2TB HDDs. Firmware v1.05 is the first version to support advanced format disks (AFD). Virtually all new HDDs released on the market today are AFD (and almost all new 2TB HDDs), although I cannot say which models will work correctly with the DNS-343. I can say that formatting HDDs as individual standard volumes rather than one RAID-5 array will yield a greater likelihood of success.

DNS-343 - Cumulative Firmware Release Notes


This marks my last post of the year 2013!  

[desau13]

Success!

http://forums.dlink.com/index.php?topic=57193.msg223363#msg223363

[JavaLawyer]

I would carefully monitor your new RAID-5 array very closely to ensure the array maintains its integrity. I also strongly recommend maintaining an external backup of your data at least until you are 100% sure the array is stable.

As always, I must stress that a RAID-5 array is not considered a backup and you should keep an external copy of any critical data.

I hope that congratulations are in order. Please post back in a month after you've had a chance to burn in your new HDDs. I'm sure there are many other DNS-343 owners eager to learn of alternative HDD options.