help choosing RAID version for new TS-451

[heckofagator]

Hi everyone,

I currently have a HP MediaSmartServer and just jumped on a deal for a QNAP TS-451.

With the HP, I liked the idea of duplication and the ability to chose which folders to duplicate. Additionally, I liked the ability to use different sized drives and just have them added to the big pool.

That being said, I think (I don't know RAID very well) that I'm probably losing a bit of this functionality with the RAID setup's offered by the QNAP. Can anyone make a suggestion which drive option I might want to chose when setting this up?

I don't have any particularly mission critical data on the server. The most important is probably pictures and home videos. I'll have those backed up to a drive on my PC, too. Additionally, I'll have ripped music and movies, but I can always re-do those later if necessary. I want to keep it fairly safe and would be ok losing 1 HDD and having the data on another while I work on the failed drive's replacement.

Thanks in advance!

 

[stevech]

Preaching warning:

"RAID IS NOT A BACKUP".
It sometimes allows you to recover from a drive failure. But it's self-defeating in a way, for small NASes (4 bay and less) - more drives for striped RAID, more probability of drive failure!

Home and SOHO use, I use 2 bay without RAID. Two volumes. My NAS's "time backup" has the second drive/volume keeping a file version history (last n versions of files in key folders). I also have automated backup to USB3 drive.

Family photos are irreplaceable. I also minimize what data is stored on PCs (and not backed up well) - and get in the habit of putting it all on the NAS. Hard habit to make.

Opinion: Drive failure is way down the list of data-loss causes, below human error, file system corruption, THEFT, and others.

 

[heckofagator]

thanks for the thoughts. We have SOS backup.

Just looking for a little drive redundacy, so I don't have to re-rip all my media. My CD's and movies too months, and I just thought it would be nice to have the ability to remove and replace a bad drive without losing anything or having to restore from backup. Maybe RAID5?

 

[nagle3092]

thanks for the thoughts. We have SOS backup.

Just looking for a little drive redundacy, so I don't have to re-rip all my media. My CD's and movies too months, and I just thought it would be nice to have the ability to remove and replace a bad drive without losing anything or having to restore from backup. Maybe RAID5?

I just got the TS-451 as well. I personally went with Raid 10 because rebuilds will be faster since its just a read/write. Also it provides actual redundancy, Raid 5 gives you parity. You lose space but I like the extra piece of mind.

 

[JoeJoe]

RAID5 would be good.

What you could do with the single NAS unit is put 4 drives (3TB or so each ) in it, configure drives 1,2,3 in RAID5 and then disk 4 as a single drive.

That would give you a little less than 6 TB for the RAID5 and 3 TB for the single disk.

Then you can have a copy process that copies the important data from the RAID5 disk to the single disk. Run that process once a week.

Or you could have two RAID1's, do something similar.

+ of course, copy off to another NAS for safer backup.

 

[radix]

thanks for the thoughts. We have SOS backup.

Just looking for a little drive redundacy, so I don't have to re-rip all my media. My CD's and movies too months, and I just thought it would be nice to have the ability to remove and replace a bad drive without losing anything or having to restore from backup. Maybe RAID5?

I don't follow the concern about "re ripping,etc".

Like stevech, I run simple drives on my 453, and back up to usb3. The data on the USB drives is exactly the same as on the NAS - so no re doing anything is required.

I don't see the value at all of adding the complexity of raid, more drives to fail, more cost. In the event if a failure, I can still access my data on the USB, and copying the data bac after replacing a drive is simple.

Since you need a non raid backup anyway...?

 

[htismaqe]

I don't follow the concern about "re ripping,etc".

Like stevech, I run simple drives on my 453, and back up to usb3. The data on the USB drives is exactly the same as on the NAS - so no re doing anything is required.

I don't see the value at all of adding the complexity of raid, more drives to fail, more cost. In the event if a failure, I can still access my data on the USB, and copying the data bac after replacing a drive is simple.

Since you need a non raid backup anyway...?

What he's saying is that he has physical copies of all of his music and movies. If he lost a drive, and thus lost all of his files, he could recover them from physical media. Backup for him is less about criticality and more about saving him the time and trouble of having to rip everything again.

 

[wchpitt]

It would depend on the drive size

After reading this article: http://www.zdnet.com/article/why-raid-6-stops-working-in-2019/
My rule of thumb is with four disks or 2TB or less, raid5 is ok, any larger a disk 3TB+ you would want to run raid6
Raid 10 in a 4 disk array would would yield the same storage capacity but faster write speeds.
Assuming 4-2TB Drives (8TB Gross)

Raid5=6TB net = Single drive failure
Raid6=4TB net = Any 2 drives fail
Raid10=4TB net = Any single drive or 2 specific drives (2 mirrors can fail but two of the same stripe may not)

RAID 6 has a write penalty compared to RAID 10. If the main thing you do is somewhat write intense and/or high concurrent writes, then RAID 10 may be a better choice.
Reads will be about the same.

Once you go to a 6bay NAS with 6-2TB drives Raid10=6TB vs Raid6=8TB

Another good idea is to buy your drives from different vendors at different times. This MAY result in you getting different manufacturing batches. Why should you care? Because if there was a run defect in a particular batch you are less likely to incur similar failures at a similar time. E.G. 4 1.5TB drives purchased at the same time from the same vendor all failed within six months of each other. 4 other drives of the same make/model with different date codes from 2 different vendors bought a week later are all still running. All drives are out of warranty so I cant really complain, but its worth making a mental note of. When we populate our fiber SANs at work we typically mix drives from different vendors AND manufacturers within a single chassis for this very reason.

 

[stevech]

5-10 years ago, I and others suffered too-frequent drive failures.

more recently, quite rare.

More likely data loss from other causes.

Argues against letting RAID drive everything and not reducing risk much.

 

[radix]

After reading this article: http://www.zdnet.com/article/why-raid-6-stops-working-in-2019/
My rule of thumb is with four disks or 2TB or less, raid5 is ok, any larger a disk 3TB+ you woul......ote of. When we populate our fiber SANs at work we typically mix drives from different vendors AND manufacturers within a single chassis for this very reason.

But then there is this conclusion from your quoted article -

Home users can relax though. Home RAID is a bad idea: you are much better off with frequent disk-to-disk backups and an online backup like CrashPlan or Backblaze.

Not feeling the benefit of adding more drives to fail just so I can rebuild them vs. recopy them. With the USB we still have good availability, albeit not seamlessly.

 

[stevech]

Problem with on-line backups is
Most of is have an ISP with way too slow uplink - like my cable modem's 35-down, 5Mbps up. Silly slow for gigabytes.
Some, like iDrive, don't charge to mail-in a big multi-disk backup drive, once a year or so. Then you're uploading deltas. Others charge for mail-in-drive.

And
I would NOT put in the cloud ANY personal/financial data. Encrypting it with their encryption is not private. Not. Encrypting it with winzip or SafeHouse-software or some such, then uploading that is OK. But I prefer to not. Just lots of copies on many media, some away from the eyes of burglars.

 

[RaptorWatcher]

Hi everyone,

I currently have a HP MediaSmartServer and just jumped on a deal for a QNAP TS-451.

With the HP, I liked the idea of duplication and the ability to chose which folders to duplicate. Additionally, I liked the ability to use different sized drives and just have them added to the big pool.

That being said, I think (I don't know RAID very well) that I'm probably losing a bit of this functionality with the RAID setup's offered by the QNAP. Can anyone make a suggestion which drive option I might want to chose when setting this up?

I don't have any particularly mission critical data on the server. The most important is probably pictures and home videos. I'll have those backed up to a drive on my PC, too. Additionally, I'll have ripped music and movies, but I can always re-do those later if necessary. I want to keep it fairly safe and would be ok losing 1 HDD and having the data on another while I work on the failed drive's replacement.

Thanks in advance!

Hi. I have had experience with RAID 5 and do NOT recommend it. It is fine when it is working but as soon as there is a disk failure the system is stressed to rebuild. It takes VERY long to rebuild.. and if you encounter what I had.. an Unrecoverable read error then the ENTIRE array goes down and it is stuck in an infinite loop for days. I suspect that RAID 6 is only slightly better. After the failure I did some research and decided on RAID 10. If any disc goes down the system rebuilds one mirrored side while accessing data from the other mirrored side. It thought is still not perfect. The capacity with RAID 10 is its downfall however since it is 2X the capacity of the discs used in a 4 disc array.
Now NAS's are getting better and the CPUs used are more and more powerful so I suspect that rebuild times will be shorter... However the dreaded URE rate will increase since the size of discs increases thereby making the threat of taking down the whole array even greater.

 

[stevech]

I read so many RAID 5 horror stories where the rebuilds fail way too often, on many different products.

 

[Trexx]

I have been using RAID-5 for the last 3 years on my old qnap (just upgraded to 453). Had one drive to "flakey" and pulled it and let it do a rebuild and worked fine.

With "Home" nas's where the raid is SW, there is always a risk, which is why BACKUPs are required to go along with RAID. Even if my raid-5 were to go south, I can still restore my data from backup to a new rebuild raid if worse comes to worse.

 

[coxhaus]

If you are going to run RAID make sure you have a good UPS especially if you are doing software caching as it is very easy to corrupt a RAID with a power glitch.

 

[Trexx]

Agreed... I have a CyberPower 1300 backing mine up.

 

[stevech]

If you are going to run RAID make sure you have a good UPS especially if you are doing software caching as it is very easy to corrupt a RAID with a power glitch.

or a NAS power supply failure or mainboard failure.
For home/SOHO, I don't recommend RAID.

 

[coxhaus]

Even if you don't run RAID and run just hard drives. If you don’t have a UPS make sure you have write through cache set. Caching writes on the hard drive will speed things up but is dangerous without a UPS.

 

[stevech]

Agree. I have a 1500VA UPS in the garage which feeds the NAS, main desktop PC, router, switches.
Some of that is in the garage, some is in the office which happens to adjacent to the garage and I use the common wall for data/power cables.

 

[sfx2000]

The default install is RAID5 - and for most folks, perhaps that's good enough...

However, if things go wrong... RAID5 likely will recover (perhaps) on a single drive failure... lost another drive, and you're in barney if you've not rebuilt the RAID set...

There's also performance considerations with most NAS devices, as they use Linux MDADM, which is software RAID, and RAID5, while it work, does put a write penalty here, as the CPU must work thru the math to sort out what drives to write, and how to calculate the parity bits and write it to the stripe...

RAID10 takes a bit of a capacity it, but look at it as two RAID0's paired up as a RAID1 - so any single drive fails, you're still in business, just like RAID5...except much faster - on both IA and ARM, esp on ARM...

Of course, goes without saying, RAID is never a substitute for backups...