Best solution to have the backup nas recoverable/failure resistant

[Smallnetener]

Hi all,
A NAS for small private LAN is going to be purchased.
Some requirements the NAS is asked to meet however go towards rather small enterprise.

The very first question is as described below.
The main usage/application will be the storage of backup files produced by clients working in LAN. Each client uses currently different methods and software solutions (operating locally on the client) for backing up its data.
NAS is not planned to be in steady operation.
Just as files need to be copied/moved onto nas the device will be pushed in operation by responsible person. It is planned to be in operation just for the duration of moving files to nas.

There are backup types/methods used and types of data the made backups are comprised of where it is important to have a backup chain of some depth.
I mean here full backup + incremental's (differential's).
Whole backup chains are going to be stored on NAS.
It is critical for lan users to have access to the backup chain on demand.
It means the NAS must be resistant against data failures,
or it will need a backup solution.

I don't like to setup a backup nas for the main backup nas.

What solutions are possible to achieve to aimed goal?
Is it an appropriate RAID array?
If yes, a raid of which type, the 5 one?

 

[thiggins]

RAID is not backup. The rule is never to have critical data stored on only one device. If you are comfortable with having all the backups stored on the NAS disappear when the NAS fails, then don't have a NAS backup.

RAID 1 is the simplest RAID level and easiest to deal with when it fails. But it has a 50% overhead, i.e. if you want 1 TB of storage, you need two 1 TB drives in the RAID 1 volume.

 

[stevech]

I like the notion of 3-2-1 for storage

3 copies
2 different media (NAS is one, other hardware like external USB/eSata is another)
1 off-site or out of thieves' sight.

on-line backup - not viable for me. My ISP upstream speed is way too slow for even incrementals.
On-line is fine for photo sharing.

 

[Smallnetener]

Hi,
Thanks for your feedbacks.
I didn't claim no one time RAID was a backup solution/technology.
It is just mine idea to spare a backup system for a huge backup system.

As mentioned it is about a nas to be used as storage for backups made
on devices in private household. Two nas won't be acceptable in this private home, first as main backup storage, second one as backup storage for main backup system.

Online is not acceptable if to consider bitrates available in my region for
getting connected with I-net. Also if to consider generally serious issues regarding data privacy nowadays. Also no acceptable if to consider the amount of data being in focus.

It seems to be not the optimal time for this discussion - Christmas, then New Years Eve. Maybe me should try to wait up some weeks until the times get more calm.

 

[stevech]

Many of us "preach" that RAID is not a backup, because too often people put a lot of data on a RAID NAS and when (not if) it fails for one of many reasons, they've made no backup to other media.
Such as a large disk in a USB3 or eSATA enclosure.

 

[Butzi]

RAID 6 will give you better availability, in case of drive failure(s) in the NAS. Remember, if one drive in a RAID 5 array fails, all of a sudden the array is now operating as RAID 0. Scary thought, especially when you replace the bad drive and push the NAS to harsh duty during the rebuild process. Murphy's law says that's when one more drive will fail, and you have no way of rebuilding the array!

If the NAS has an eSATA connection, there are lots of cheap eSATA drive enclosures that will allow you to back as much data as you want onto another device, which you can relocate after the backup process is complete, thereby giving you off-site backups. Take it to work, give it to a friend or family member, or run fiber over to your neighbor's house. It's not that hard to have secure offsite storage, without sending your data over the internet.

 

[stevech]

RAID 6 will give you better availability...

Indeed, until your NAS has a LOT of drives, many feel that other errors are far more likely than drive failure. No matter the cause of data loss, an outside, different-media backup is essential.
Some causes

• Human error (deleting or overwriting)
• Theft of NAS (very likely)
• File system corruption
• NAS power supply or mainboard failure and user doesn't have software drivers to read Linux formatted disk(s) on PC/MAC, etc.
• RAID recovery software doesn't work
• Drive Failure

Lots of horror stories on this reliance on RAID to do more than the last in the list.

 

[Butzi]

Even simpler

I bet if we did a survey and asked people if they had spare, identical drives sitting on the shelf for their NAS, in case of drive failure, at least 25% would have to say NO.

Indeed, until your NAS has a LOT of drives, many feel that other errors are far more likely than drive failure. No matter the cause of data loss, an outside, different-media backup is essential.
Some causes

• Human error (deleting or overwriting)
• Theft of NAS (very likely)
• File system corruption
• NAS power supply or mainboard failure and user doesn't have software drivers to read Linux formatted disk(s) on PC/MAC, etc.
• RAID recovery software doesn't work
• Drive Failure

Lots of horror stories on this reliance on RAID to do more than the last in the list.

 

[stevech]

That's why my USB3 2TB drive gets a very frequent and automated backup of all VIP folders on my NAS. And my VVIP folders go to a 32GB SD card in the NAS, encrypted.

 

[Smallnetener]

Thanks a lot for all your feedback.
And, I apologize for the lag on replying on it.
Lot's of other similar or more important tasks these weeks.

My job is make decision regarding solution optimal for given situation.
No much time resources available, so please have understanding
I aim the decision without diving into deep technical details.
I will try to do it with flat diving as much as possible.

So, I understand RAID is not 100 per cent failure proof.
It just moves the point of unrecovery a bit upwards.
So me plans to have additional USB 3 drive as backup for backup-nas.
There is no other way out.

* I wonder if in this situation it make sense then while building raid for nas
to focus only on performance-focused raid modes.
If me will build raid for the nas, it will be an array.
Sorry, I am not permanently on the storage topic, so not sure
when does the term raid include array , when not.
* How about recovering the backup-nas or its backup from
file system errors or similar. In most cases the backups are chains
of full and increments. The full can be always recovered from original/source data.
The increments other than the last one NOT!
What is the best practice to recover old incremental backups from
file system errors, bad sectors, and so on?

Please allow me few side comments.
The off-side storage as each process on the earth is connected with
some risks. Just getting the off-site drive close to system to be backup-up
and back to its location can result in disaster. No off-site location is 100% secure.
It is just its geographical distance by what the off-site storage adds more value into concept.

 

[stevech]

IMO, the most likely need for off-site storage is risk of theft of the NAS. Thus, putting the off-site physically off-site is mostly for fire/flood. Where I live, that risk is nill so I don't do that.

For anti-theft, all financial data is encrypted by Safehouse software independent of the NAS. Then that data, and family photos, and other VIP files are backed up automaticallly to a 1 bay NAS (old/slow/cheap) that's hidden from view of thieves. And two other copies are made, one on SD card and one on USB flash that is out of view and with me at all times.

WIth a 2 bay NAS (all I need), I don't use RAID as IMO, it makes no sense with 2 bays, vs. using 2 volumes.

 

[Dennis Wood]

It gets a bit more complicated when you consider that you really should also keep a backup rotation. We had an unfortunate incident in October in that one of our accounting workstations picked up an encrypting virus from an email. This virus, although cleaned up within hours, encrypted all the office files, and about a year's worth of document scans on the workstation. We were crazy lucky in that this workstation has no mapped drives, as it would have been far worse. The part-time book-keeper did not realize that all old files had been encrypted (irrecoverably) until nearly 3 weeks had passed..as all new files were ok. Well, all the backups from that workstation had encrypted files in them...

My mistake was not having longer rotations on the workstation images...so although every workstation in the network fully images itself nightly, the schedule only allowed about 2 weeks back recovery. Subsequently I upgraded a backup NAS to 12TB for workstation image backups only (allowing 4 wks rotation) and then used the same "backup" NAS as an rsync backup host for NAS 2 and NAS 3 (production units). We also rsync nightly (and now, monthly snapshots) offsite for critical data. Rsync is very efficient, secure, and automated on the NAS units.

Many assume that their web sites are also backed up..and generally, they are not. Using RRTR (part of the QNAP NAS OS) and given 4 NAS units, in two locations..we efficiently replicate about 20GB of web data, again in nightly, weekly and monthly snapshots. SQL data on the web databases backs up via CRON jobs on the host..then replicate back to the NAS units.

It seems extensive but most of the challenge is in planning...implementation is pretty quick.

 

[Smallnetener]

WIth a 2 bay NAS (all I need), I don't use RAID as IMO, it makes no sense with 2 bays, vs. using 2 volumes.

In my two bay nas I use RAID 0 array for more performance + external additional storage
for more reliability. RAID 0 for more performance, does it not make a sense? Sorry for the question, I am a storage user, not expert.



By the way, if RAID in none of its known modes is a backup following question arise on my side.
As far my current understanding is, there are raid modes addressing
both the aspect of performance and aspect of more data storage reliability.
Several raid modes use/generate redundant data for more data storage reliability.
What is then the sense of these efforts if raid does not provide the backup functionality?
One could simply forget these modes/efforts. Sorry again for this question, I am a storage
user, no storage expert.

 

[stevech]

Use RAID0 only if you have a robust and frequent backup method, e.g., to a USB3 drive.
Personally, I'd never use RAID0 due to risk.