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RAID10 format time
#1
Hi all,

My RAID5 died (second disk failed while it was rebuilding from a first disk failure), but luckily (albeit expensively) I was able to recover all data.

Now I'm building a 4-disk RAID10 on N4100PRO with FW 5.03.02 and I'd like to do a reality check on the build time. I have 2x3TB disk and 2x2TB disks in it. I selected RAID10 and "quick". The device is still saying "Format RAID" after 16 hours. Is this expected? Is there a calculation on how quickly (slowly) it should create the array?

Thanks.
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#2
1) Good for you - Raid5 is such a bad idea in these days of cheap, huge HDDs. 
I've seen a 1.5TB RAID5 rebuild take three days (yes!) on a fast desktop computer.  This opens a very large window such that you might lose a 2nd drive, and thus the whole RAID.  Aaaand, the RAID is essentially unusable (molasses-slow) while it's rebuilding.

If you ever have to rebuild your RAID10: once the first few tracks of your RAID are rebuilt - which takes a minute or so - you'll find that your NAS is completely usable (and back to normal speed) while it's rebuilding.

2) It's been pointed out here, over and over, that leaving the Storage/RAID Management page open in your browser slows down RAID formatting and rebuilding considerably. This might be your problem.

3) I can't remember exactly how long it took to format the RAID1s on my system when I first set it up - but it was only a few hours per RAID. 

I regularly swap out two out of four HDDs (one from each of the two RAID1s on my system) to store them in fire-proof storage, and swap in two HDDs (pulled from that storage).  After the NAS completes its boot up, I insert one the of the not-current HDDs, wait a few seconds for the rebuild of that RAID to start, then insert the other HDD for the rebuild of the 2nd RAID.  

My NAS thus rebuilds both 3TB RAID1s at the same time.  This rebuild (2 x 3TB) typically takes about 12 hours - not per but total.  Formatting a 4TB RAID10 should take - at the very most - six hours (more like two or three, if you ask me, the '0' part of the RAID gives you nearly double the data throughput).

So: if you ask me, after 6 hours of formatting a 4TB RAID10, I'd declare that formatting failed and restart; with '2)' as a caveat.

You may have to delete any partitions/data-partitions from the HDDs for a clean reformat.  If you need to do so, you can use Disk Manager in Windows to delete them, providing you can connect your HDDs to it.  SATA are drives are generally hot-swappable.
Thecus N5550 (CPU: D2550 @ 1.86GHz, BIOS: 2.05.14.5.cdv X64)
Disks: 5 x 3TB Seagate NAS-class; 2 x 3TB-RAID1 plus Hot Spare
Memory: 8125 MB (2 x 4 GB Corsair 204-Pin DDR3 SO-DIMM 1333)
Apps: Too many to count....
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#3
(11-14-2016, 12:47 AM)ThaumaTechnician Wrote: 1) Good for you - Raid5 is such a bad idea in these days of cheap, huge HDDs. 
Yes, when it was first built (which was probably more than 6 years ago) I only had 3 drives and I think N4100Pro didn't support RAID10 then anyway.


Quote:2) It's been pointed out here, over and over, that leaving the Storage/RAID Management page open in your browser slows down RAID formatting and rebuilding considerably.   This might be your problem.
I have read that and the browser is closed - I only open it to check on the NAS from time to time.

Quote:So: if you ask me, after 6 hours of formatting a 4TB RAID10, I'd declare that formatting failed and restart; with '2)' as a caveat.

You may have to delete any partitions/data-partitions from the HDDs for a clean reformat.  If you need to do so, you can use Disk Manager in Windows to delete them, providing you can connect your HDDs to it.  SATA are drives are generally hot-swappable.
Ok, thanks - now that I know it's too long, I'll see what's happening. I have sata-to-usb cables, so can plug them into a Windows box and will delete any existing partitions in there then.
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#4
It's strange, but the RAID is not coming up. It has finished creating (quick one never worked, so I went with normal creation) - got to 100%, I rebooted and it says there's no raid. Could it be a faulty controller in the unit or something?
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#5
(11-15-2016, 05:40 PM)dvlpr Wrote: It's strange, but the RAID is not coming up. It has finished creating (quick one never worked, so I went with normal creation) - got to 100%, I rebooted and it says there's no raid. Could it be a faulty controller in the unit or something?

Does Windows/Disk Manager show any partitions?  You won't be able to read the data on them, but it should show the partition structure.

Are the HDDs listed in the compatibility list?
Thecus N5550 (CPU: D2550 @ 1.86GHz, BIOS: 2.05.14.5.cdv X64)
Disks: 5 x 3TB Seagate NAS-class; 2 x 3TB-RAID1 plus Hot Spare
Memory: 8125 MB (2 x 4 GB Corsair 204-Pin DDR3 SO-DIMM 1333)
Apps: Too many to count....
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#6
I haven't checked in Windows, but after that I tried creating a quick RAID6 and that worked. Then I started RAID10 creation again (quick) and it's been stuck in "formatting" for over 12 hours now. Is there any issue/trick to create RAID10 on this particular unit? FW is the latest 5.03.02.
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#7
Tried quick RAID6 again and it works again - something must be preventing RAID10 from being created. Could it be because not all disks are same size? I'll stick with RAID6 for a bit then, since I need to move data there. Perhaps one day I'll get back to this issue to see if I can re-create RAID10 again.
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#8
(11-16-2016, 12:11 PM)dvlpr Wrote: Tried quick RAID6 again and it works again - something must be preventing RAID10 from being created. Could it be because not all disks are same size? I'll stick with RAID6 for a bit then, since I need to move data there. Perhaps one day I'll get back to this issue to see if I can re-create RAID10 again.

The RAID is supposed to use the smallest disk's size as the basis for the size of the RAID.  If you have drives that are almost the same size, it's not really a problem, but if your drives are substantially different in size, you'll be losing a lot of storage capacity.  What drive sizes do you have?

 Maybe the formatting routine isn't calculating the RAID size properly, or is trying to format non-existent disk capacity?  Your model, when first released, couldn't build a RAID10.  Maybe it still can't really.  Mind you, RAID6 does use striping...

An alternate solution is to pair up the drives and have two separate RAID1s. 

It's what I've settled on because I wanted to be able to swap out and in drives for safe fireproof storage.  It's a tiny bit of a pain, because I don't have one large 6TB partition but rather two 3TB partitions, but it's working fine for me.  I store some kinds of stuff in one, other kinds in the other.  The possibility of swapping out drives for storage is what's important to me.

Rebuilding both RAID1s (3TB each) at the same time, when I swap out/store/swap in drives, takes about twelve hours.  Performance/usability of the NAS isn't affected at all during rebuild and if the system/hardware/rebuild crashes completely, I have a complete working backup of the NAS.
Thecus N5550 (CPU: D2550 @ 1.86GHz, BIOS: 2.05.14.5.cdv X64)
Disks: 5 x 3TB Seagate NAS-class; 2 x 3TB-RAID1 plus Hot Spare
Memory: 8125 MB (2 x 4 GB Corsair 204-Pin DDR3 SO-DIMM 1333)
Apps: Too many to count....
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