RAID setups

Livin The Dream

Livin The Dream

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So I have been running a 4 bay NAS with only two drives on RAID 1 for a while. Now I have the NAS back after a hardware failure and two more drives I was looking at migrating to RAID 5. Just been reading a bit more and looks like RAID 6 is a better option for higher capacity HDD's.

All 4 drives are 3TB so is this a better option?


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I wouldn't have thought the disk sizes are relevant to be honest, although someone please correct me if I'm missing something!

I've always spec'd RAID5 + hotspare as a minimum in servers as it supposedly has a performance benefit over RAID6 (not massive but every little helps), although RAID6 has better rebuild performance should something go wrong. Data integrity is paramount and I prefer the resiliency of being able to withstand 2 disk failures as I've seen scenarios with multi-disk failures occurring within days of each other.

Either a RAID5+1 or RAID6 scenario should be equally beneficial, unless you intend to run RAID5 over the 4 disks resulting in additional volume space.

I've also scene RAID6 have a larger overhead in terms of storage, not a lot to be honest but it was there.
 
RAID5 on four 3TB drives is a good setup and one I used for some time. I really wouldn't use RAID5 on fewer (i.e. three) or RAID6 on less than five as, if a drive fails, you're then below the number that that RAID level supports. I did some research when I built my eight-drive-bay server and the general consensus seemed to be that there's no reason to run RAID5+1 if you can run RAID6 but, on four drives, RAID5 is all you need.
 
But regardless of the minimum supported amount of disks you can only tolerate a single disk failure in a RAID5 volume, hence the need for a hot-spare or RAID6 where parity information is written to 2 disks.
 
Neilc28 said:
But regardless of the minimum supported amount of disks you can only tolerate a single disk failure in a RAID5 volume, hence the need for a hot-spare or RAID6 where parity information is written to 2 disks.
Click to expand...

That's what I have been reading plus many seem to think that above 1TB disks RAID 5 isn't very stable?
 
It depends on the controller and the hard disk. Perhaps in your NAS RAID5 above 1Tb is not recommended due to the controller.
 
Its not so much the 'stability'. It's more due to the downtime of the raid when a disk fails & the possibility of another disk failing when its rebuilding itself.
RAID 5 is going 'out of fashion' using 'very large drives'.
hence
RAID 50..
 
RAID50 is not supported by the average RAID controller in a NAS though, in fact I would estimate that most of the users here don't have NAS appliances with enough bays to facilitate RAID50 in the first place.

It may be becoming the norm in enterprise but for SMB or personal use then 1/5/6 are very much the norm.
 
There are limits though on what a cheap RAID contoller can handle.
 
However, I use RAID 5 on my NAS (can use 50!). 4 x 3TB & everything is copied to a hot spare disk kept at my mums house. When thats full I'll just add another. If the RAID fails, I'll remove the faulty drive, attempt to rebuid (using new drive) then if that also fails - break the RAID & restore from backup drive.
 
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I think I have a bit to consider.

I originally invested into a NAS to safeguard against disk failures and to stream my music and films to devices in the house. The main flaw though is that my current backup system doesn't cover me away from home.

I use the NAS in the living room as a server with Xbmc for films. More recently I had moved my master lightroom files back to the Mac because of the lag in the system.

I have 300gb of photos at the moment and 200gb of music that I want to have a fail safe backup system for. My film collection I am not too bothered about but have 1.3TB worth.

Given I have 1TB on the Mac; 2TB external and 4 x 3TB NAS can't quite decide the best way forward. What suggestions do you have?
 
You can run 2 X RAID 1 in the NAS, buy a 5th disk as a cold spare and make sure you get alerts from the NAS.
 
Ignore me, I'm an idiot, noticed 'cold' spare now lol
 
I assume a disk put aside (outside of the NAS) to replace a failed disk should that event happen. Difference being it requires users intervention whereby a hot-spare will be in situe already and automatically take over in most cases.
 
Try this:
Copy files from camera to Laptop & the external 2TB.
Work on files on laptop.

Once edited, copy the files to the NAS setup as a RAID 5 - 4 x 3TB & overwrite the External 2TB (once on the NAS).
Also copy to another 1 x 3 TB & use that as a BACKUP DRIVE - only connected to the system to add files to it - kept offsite. Once full get another.

Notes:
Only use the MAC 1TB to work on the files to be edited. Once edited & on NAS & external remove from laptop.
Use the External 2Tb as a portable drive containing THIS YEARS pictures ONLY.....
 
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I prefer the set and forget approach where its mostly automated with alerts automatically generated as and when.
 
Away from home copy from Camera to laptop & external drive. If you require more storage (than the space on your laptop) - bear in mind this is TEMP storage only - then get another external drive (2Tb).
 
BTW - I copied 1.3TB (32,000 pictures) this year using this method.
 
Actually Pete that sounds a decent enough workflow. I think a 3TB offsite is the extra I should do really. Thanks for the input.
 
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