[SOLVED] Best RAID/SHR type for 4 bay NAS

[clemsontigerblah]

I am wanting to setup a NAS for my household. Plan for it to be multipurpose, but mainly to provide area for computers on network a place to backup/share data and possibly a media sever in future. I bought a DS920+ and was going to populate with 4 Ironwolf 8TB drives. The reason I chose larger HD was because I got a good deal on them plus I was originally going to use RAID6 so wanted to have plenty of space. I had chosen RAID 6 based on some research I did which scared me from using RAID 5 due to the size of the drives and probability of URE, etc. However, now that I have read more, it seems that using RAID 6 on a home 4 bay NAS (which doesn't need to be up 24/7 like a business might), RAID 5 may be better choice for performance and space. Also, am learning more about SHR/SHR2 and seems like that would be better choice than RAID5/RAID6 anyway.

So here is the question:
For the size of drives I am using and the fact that it may not be crucial for the NAS to be up 24/7, is RAID6/SHR2 worth the drop in capacity and slow down compared to RAID5/SHR and is there any reason not use SHR/SHR2 instead of RAID equiv?
Also, if using RAID5/SHR, should I consider using just 3 drives and keep the 4th as a backup to swap out, or would that just be a big waste of money since it will likely just sit there unused?

Thanks.

 

[USAFRet]

First off...
In your own words, why RAID 5 or 6?

 

[jeremyj_83]

SHR is basically RAID5 and SHR2 is basically RAID6. RAID5 offers the ability to have a single drive failure and RAID6 allows for 2 drives to fail. That also comes with the same level of loss of space. A 4 disk RAID5 for you will have 21.8TB of usable storage vs 14.6TB for RAID6. Are you able to sacrifice that extra 8TB? In terms of performance you will have better performance with a RAID5 vs RAID6, however, since this is a home network you are most likely on GbE anyways so you will never notice that difference.

Where I work we don't use RAID5 or RAID6. Our storage arrays are configured using RAID50 & RAID10. You do not have enough disks to use RAID50 as that is 6 disk minimum. However, for home use I personally would just run a RAID5. You have gotten good quality HDDs so your odds of a disk failure over a 5 year lifespan is something like >1%.

RAID Reliability Calculator | Simple MTTDL Model | ServeTheHome

ServeTheHome's RAID reliability calculator based on a simple MTTDL model based on a Poisson distribution and various user inputs about their environment

www.servethehome.com

 

[USAFRet]

RAID 5 is contraindicated for 8TB drives. Rebuild time is far too long.
RAID 6 will require all 4 drives.

For ANY RAID situation, you still need a known good backup procedure.


In my NAS situation, I've gone away completely from any RAID.
When I first stood it up, RAID 5. 4x 3TB, just to experiment. Later, upgraded to 4x 4TB.
Currently, 8TB + 8TB + 16TB + 480GB (SSD system drive).
All single drives, single volumes.

Full backup weekly to a 4x 4TB JBOD thing in an external box, attached to the QNAP.


Given good backups, RAID is mostly a waste in the consumer space.

 

[clemsontigerblah]

First off...
In your own words, why RAID 5 or 6?

Wanting to have some degree of redundancy in case of drive failure. For that reason with 4 drives, RAID 5 or 6 seemed most logical choice. I've seen arguments for both and just wanted to get opinions on what most would use in this situation.
Also, after reading on SHR, trying to see if there is any reason why I wouldn't just use SHR/SHR2 rather than RAID equiv.

 

[USAFRet]

Wanting to have some degree of redundancy in case of drive failure. For that reason with 4 drives, RAID 5 or 6 seemed most logical choice. I've seen arguments for both and just wanted to get opinions on what most would use in this situation.
Also, after reading on SHR, trying to see if there is any reason why I wouldn't just use SHR/SHR2 rather than RAID equiv.

The RAID is only good for drive redundancy, and if you need actual 100% uninterrupted uptime.

You still need a good backup routine for data redundancy.
And if you can survive through an hour or two of recovering from a backup....you don't really need the RAID.

Unless you're running money making webserver or similar, you don't really need that uptime on the data in the NAS.


My current NAS is individual drives.
Each of the 4 has its own use.
1 for the system drive (480GB SSD),1 for the house camera recording, 1 for all the house systems backups, 1 for all that other stuff (movies/music/etc)

If any of the physical drives were to die....slot in a new one, and recover that data from where it is backed up. No hassle with rebuilding the RAID, no data on any of the other drives is affected, etc, etc.

When I went from 4x 3TB to 4x 4TB RAID 5, I also did it with jsut slotting in a new drive, simulating replacing a dead one.
The RAID 5 rebuild in my QNAP takes approx 1.5 hours per TB of consumed space. RAID 6 would be similar.

So if your array had 10TB actual consumed space....that rebuild time would be....'come back tomorrow'.


Physical drive fail is only one of the pathways to data loss, and actually the least likely.
So you need an actual backup anyway.


At the consumer level, I've found the RAID concept to be just a waste.
Just my $0.02.

 

[clemsontigerblah]

The RAID is only good for drive redundancy, and if you need actual 100% uninterrupted uptime.

You still need a good backup routine for data redundancy.
And if you can survive through an hour or two of recovering from a backup....you don't really need the RAID.

Unless you're running money making webserver or similar, you don't really need that uptime on the data in the NAS.


My current NAS is individual drives.
Each of the 4 has its own use.
1 for the system drive (480GB SSD),1 for the house camera recording, 1 for all the house systems backups, 1 for all that other stuff (movies/music/etc)

If any of the physical drives were to die....slot in a new one, and recover that data from where it is backed up. No hassle with rebuilding the RAID, no data on any of the other drives is affected, etc, etc.

When I went from 4x 3TB to 4x 4TB RAID 5, I also did it with jsut slotting in a new drive, simulating replacing a dead one.
The RAID 5 rebuild in my QNAP takes approx 1.5 hours per TB of consumed space. RAID 6 would be similar.

So if your array had 10TB actual consumed space....that rebuild time would be....'come back tomorrow'.


Physical drive fail is only one of the pathways to data loss, and actually the least likely.
So you need an actual backup anyway.


At the consumer level, I've found the RAID concept to be just a waste.
Just my $0.02.

Thank you for your $0.02. Sounding like RAID not worth it and I should consider sending the drives back to Amazon and getting some cheaper 4TB ones.
In regards to backing up data, I understand RAID isn't a backup, but just seemed like something that everyone did on their NAS and sounded like a good idea.

However, I am also wanting to use the NAS as a place to backup all the computers in the house which I have traditionally used several external drives.
This was a hassle so was hoping a NAS would let me do it more in a more automated fashion on continuous basis in a central location that was accessible by all the computers.

I also use Backblaze cloud to backup the computers (to act as offsite backup), but have terrible internet with extremely slow up speed (took a month or so to do a new backup of about 2 TB of data), so this is not a good solution to quickly restore important new files (such as large raw images my wife needs for her photography business), so might also use the old external drives as archives and keep at my office.

Thoughts?

 

[USAFRet]

No, those physical drives are FINE. Don't return them.

For your house systems backing up to the NAS. Absolutely.
My house systems do that every night, every other night, or weekly, depending on the system.

Macrium Reflect, all on individual schedules.

What is your backup situation at home?

What is your backup situation at home? And if you don't do that, why not? Every single day, I read multiple threads here of "How do I get my stuff back?" or "That drive had 5 years of photos of my kids!!" Be it a dead drive, dropped phone, virus, accidental deletion, formatting the wrong...

forums.tomshardware.com

I have actually needed to use that after the death of an SSD in my main system.
960GB SSD, 605GB data on it.
Slot in a new drive, click, click in Macrium...wait an hour...100% recovered, exactly as it was at 4AM that morning.