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What would be my best approach

nheather

Distinguished Member
I have a Synology 216, with just one 4TB - plenty for what we need.

But recently I have had a couple of mechanical hard drives fail (not in the NAS but various other computers) and that has left me a little nervous.

The disks I lost weren’t that important and I did not lose any data but made me think that if I lost the one disk in the NAS it would be a little worse.

So thinking how to protect that disk. My first thought is, that I have a spare bay so put another 4TB drive in it. Fine with the price and as I said, 4TB is plenty for my needs. What would be the best way to approach this, two disks in a RAID 1 mirror, or two independent storage pools with a backup copying the files from the main storage pool to the backup pool.

Cheers,

Nigel
 

mickevh

Distinguished Member
I guess we should rehearse the AVF mantra that "RAID is not backup." RAID1 would avail you continued access to data if a disc dies, but it does not protect you from many other risks such as accidental overwriting or deletion, crypto locking and randsomware, flood, fire, theft and so on.

If you've not made a backup recently, I'd make one before trying to create a RAID1 pair just in case it goes wrong: You will hate yourself forever if you added disc 2, told the array to RAID1 and the first thing it did was wipe your discs...! It has been known to happen.

By "make a backup" - I mean, before changing anything on your NAS, copy the (important) data away somewhere else.

RAID, snapshots and backups all mitigate different risks and often (in business) are used in concert with each other. We can get into the weeds if you need to flesh out the discussion.

What kind of backup regime is best for you is informed by the risks you wish to mitigate and the cash you are prepared to spend, so perhaps start by thinking about it holistically: For example (and this is not an exhaustive list) - do you want to mitigate disc failure, do you need "point in time" snapshots (and if so, how many, how often, and how long do you want to keep them,) do you need to off-site the data in case of catastrophy, secure from ransomeware, mitigate accidental deletion.... Perhaps make an ordered list to determine what's most important for you, then we can explore ideas of how to achieve it most cost effectively.
 
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nheather

Distinguished Member
All appreciated. I do appreciate that RAID 1 is not a backup, it is a duplication. I included it because it does 98% of what a backup does and it does it in the background without me having to think about it. My main concern is disk failure, as I said in my original post.

And point taken about making a backup.

So what do you suggest is the best way for me to do this?

I suggested putting the second disk in as a separate storage pool and have a backup that copies from one pool to another but I‘m not even sure if that is possible with my NAS (Synology 216J).

It has USB 3.0 - so is there something that will run on the Synology and backup to a connected USB drive. Hoping something that is automated, just works in the background. But then it is probably not a good idea to leave a USB disk on all the time.

Cheers,

Nigel
 
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mickevh

Distinguished Member
If you hired me in to do the work for you I would: (again, somewhat holistically,)

  • Find the manual for your NAS and read it.
  • For the purposes of debate, let's assume the manual indicates you can non-destructively convert the array from a single disc to a RAID1 set.
  • Look to see if you have enough space anywhere (else) to back up your data.
  • If not, buy or hire it.
  • Back up the data on your NAS somewhere else. (If not all of it, certainly anything irreplaceable) Ideally, two copies in separate places and I'd check (verify) the backups actually worked with some kind of "compare" tool.
  • If you can direct attach the backup device to the NAS, it may be quicker, if not, we can do it over a network link - wired (preferably gigabit) ethernet, not Wi-Fi will usually be quicker.
  • Add disc 2 and reconfigure the array to be a mirror set (not necessarily in that order, depending on what the manual says.)
  • Leave it to mirror and go play Defender for few hours.
  • Once it's done, check the logs for any errors.
  • Maybe repeat verification that the backups match the live dataset.
  • Make another backup.

I'd disagree that RAID1 does 98% of what a backup does, but from memory you've been party to such discussions in the past, so I won't labour the point. As you say, RAID1 will secure you against disk hardware failure - just not much else - and you don't have to think about it as it "just works" without your intervention, or running some background "duplication" process.

My NAS is running a file system called ZFS which can do a periodic integrity check (called a "scrub" in ZFS speak) to check for, and if possible correct, any "silent" corruption that might occur. If your NAS offers such, you might consider using it. Similarly, if your NAS is ZFS based (or ZFS like) you might explore "snapshots" for making point-in-time images of your data. Whilst snapshots are also not "proper" backups they are usually quick and very storage efficient and a way to mitigate accidental deletion, overwriting, crypto-locking, viruses and similar processes that might alter your data that RAID1 won't save you from.
 
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nheather

Distinguished Member
I only said that RAID 1 does 98% of what backup does because you asked what my backup regime requirements are and I answered to protect against disk failure. Based on that I’d say that RAID 1 does pretty much 98% (made up number, it may be 90%, it may be 95%, it is just a commonly used expression not an exact calculation).

I’m not looking to design a data management system for HSBC, just my little NAS at home. I’m not going to employ a data manager to look after it for me. Just looking for a simple cost effective solution.

I agree that RAID 1 doesn’t do everything that backup does, I have said as much. It was just one of the three options I have identified - RAID 1, two storage pools in the NAS, use one as a backup, connect a USB disk externally to the NAS and backup to that.

And interested in any other simple and cost effective solutions.

Cheers,

Nigel
 

mickevh

Distinguished Member
Indeed - perhaps choose from the menu a bit depending on where you are happy to accept a degree of risk.

Another solution you might consider is seeing if your ISP provides any tools. I've been renewing with BT of late (just happens to be my ISP) and they currently offer something like 200GB of cloud backup on the basic packages and 1TB on some others. Or perhaps Onedrive, Skydrive and the like. Others (here at AVF) subscribe to things like Crashplan and similar service offerings.
 

nheather

Distinguished Member
I did consider cloud storage, don’t think my ISP (Sky) does it, nor am I sure that I would want to store my data with a media company.

There are other options but I’m not convinced that it makes a good recovery solution.

If I have 2TB of data and I could get a continuous 20Mbps download that would take over 9 days to recover a failed disk - assuming I didn’t hit any bandwidth limits.

I have a smallish USB drive, going to try that as an external connection and see how it works. If good, I’ll get a bigger one.

Cheers,

Nigel
 
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maf1970

Well-known Member
But recently I have had a couple of mechanical hard drives fail (not in the NAS but various other computers) and that has left me a little nervous.
If you have a look at the Synology site it has a solutions page just for personal backup -

Preserve Your digital assets

You could use Synology Drive to automatically backup your other machines to the NAS.

You could use USB Copy to copy data to a an attached USB backup drive.

You could do a backup to the Cloud.
 

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