Best Way to Back up Music Library

[DavidHB]

(04-06-2015 16:05)gnomus Wrote:  I speak from a position of ignorance, of course, but, some time back, I did see a post (I think from Simon) that pointed out that the second drive in did not provide a 'back up' as such - if a file became corrupted it simply meant that the corrupted file was duplicated.

That's not exactly the way it works. There are different sorts of RAID arrays, but the concept of true RAID is that, if a disk fails, the rest of the multi-disk system contains the wherewithal to reconstruct the contents of the failed disk on the replacement. In effect, the array repairs itself. This reconstruction is of the whole data structure, rather than of individual files, and it tends to take a long time, which is a significant disadvantage. For a fuller and more technical description, see this Wikipedia article.

(04-06-2015 16:05)gnomus Wrote:  It is a little expensive buying all these second drives, and I am wondering if I might be better off just having singles in my Synology - or setting it up as one large 6TB storage device. I'd be interested in what folks thought of this idea.

Your single large drive idea is RAID 0. Unless you really need a 6TB drive, it's actually a bad idea for a home system, because it is more vulnerable than two separate drives. In this configuration, if one drive goes down, you lose all the data on both drives. Retaining just one drive on the Synology might be possible, but you would need to reformat that drive, and would therefore lose the data on it. I don't know the specifics of this for your Synology. It is also usually possible to have a NAS treat individual disks as separate drives; again I don't know the specifics of that for your system, though re-formatting would again be required.

I thought quite hard about what sort of array to have on my NAS, largely because data redundancy means that you do not get the full benefit of all the disk space you have bought. In the end, I went with the manufacturer's default array, because it was the most straightforward to set up, and it does provide increased data security, though not to the point of making backups unnecessary.

David

[simoncn]

(04-06-2015 23:53)DavidHB Wrote:  That's not exactly the way it works. There are different sorts of RAID arrays, but the concept of true RAID is that, if a disk fails, the rest of the multi-disk system contains the wherewithal to reconstruct the contents of the failed disk on the replacement. In effect, the array repairs itself. This reconstruction is of the whole data structure, rather than of individual files, and it tends to take a long time, which is a significant disadvantage. For a fuller and more technical description, see this Wikipedia article.

This is true for a drive hardware failure but cannot protect against any other causes of file corruption such as software problems or human error.

[simoncn]

(04-06-2015 16:05)gnomus Wrote:  I speak from a position of ignorance, of course, but, some time back, I did see a post (I think from Simon) that pointed out that the second drive in did not provide a 'back up' as such - if a file became corrupted it simply meant that the corrupted file was duplicated.

It is a little expensive buying all these second drives, and I am wondering if I might be better off just having singles in my Synology - or setting it up as one large 6TB storage device. I'd be interested in what folks thought of this idea.

RAID has advantages for availability, as a RAID array can continue to function when one disk fails.

You could achieve something similar by having a secondary NAS that acts as a backup for the main NAS. If the main NAS fails, you can use the secondary NAS until the main NAS is back in operation.

RAID is not a backup and should not be regarded as a substitute for a good backup discipline.

[DavidHB]

(05-06-2015 11:57)simoncn Wrote:  This is true for a drive hardware failure but cannot protect against any other causes of file corruption such as software problems or human error.

Indeed, though the discussion began with gnomus describing a possible drive failure. And I don't know of any system that completely protects against human error. As an engineer friend of mine said, "Every time I make things foolproof, they go and invent a new fool".

David

[gnomus]

Thanks all. This 'fool' just put his brand new 3TB WD drive into his 213J. Unfortunately, I am still getting a blinking orange light and the webpage is telling me that Volume 1 is defective!

Not entirely sure what I should do now. I wonder if the new drive on its own would allow me to have a single disk 213J that actually worked. Any suggestions?

[simoncn]

(05-06-2015 13:50)gnomus Wrote:  Thanks all. This 'fool' just put his brand new 3TB WD drive into his 213J. Unfortunately, I am still getting a blinking orange light and the webpage is telling me that Volume 1 is defective!

Not entirely sure what I should do now. I wonder if the new drive on its own would allow me to have a single disk 213J that actually worked. Any suggestions?

You can run a 2-bay Synology with a single disk. I am doing this on my DS713+.

[DavidHB]

(05-06-2015 13:50)gnomus Wrote:  ... I am still getting a blinking orange light and the webpage is telling me that Volume 1 is defective!

Not entirely sure what I should do now.

You will get more knowledgeable help on the Synology forum. FWIW, I suspect, from what I have read, that you will need to get your NAS to initialise the new disk and integrate it into the array. If it is supposed to do this automatically, and has not done so, then the specialist forum is likely to be the best source of advice. If, however, there is a specific procedure to follow, my previous reading suggests that it is the section in Synology Help on repairing a degraded RAID array that you need to consult. But, as I have said before, this is not my area of expertise.

David

[gnomus]

You are probably right about the Synology forum. But for anyone reading this who might be curious, what I was supposed to do was load the new disk into the 213. Then start it up. The machine would then report that Volume 1 was degraded (which is, of course, exactly what happened - see above). It would then offer to repair it (it did offer to do this). I should have accepted that offer and the machine would then have set about integrating the new drive.

I believe that there may be ways of setting up the RAID-thingie so that you can just swap out one drive and have the whole process be automatic - clearly that is not what I had, however.

The more I have thought about this, I am less clear about what it is that the 2-disk NAS option is offering. My experience of this recent HD failure has led me to conclude that I should have just the one drive in the 213 (this is what I am in the process of doing), and use the second drive as a standalone back up. I cannot see how that is any less secure that the 2xHD NAS - indeed it may be more secure, in that the second drive can be physically located somewhere other than in the same room as the NAS. And, it will not be running most of the time like it would if put to use in the 213.

[gnomus]

Once upon a time ......

(03-06-2015 13:19)DavidHB Wrote:  ... It will be interesting to know how quickly the NAS to NAS copying task goes (the initial full run is at least a one off); I only have the one NAS, and so this is something I have not tried.

My impression is that SyncToy is not terribly quick at copying the whole library from one place to another. I am in the process of backing up the library on my 215J (NAS) to an external HD (plugged into a USB port on the 215J). I started this more than 24 hours ago and it is not yet half way through. By contrast, last night I started copying the library to my 213J from another external HD (plugged into a USB port on the 213J). As I type, it is reporting that it will be complete in ~20 minutes, which would be around 10 hours.

So for copying (backing up) an entire library, SyncToy is probably not the best option. For everything else, however, I think it is going to be extremely useful.

[DavidHB]

(06-06-2015 06:59)gnomus Wrote:  My impression is that SyncToy is not terribly quick at copying the whole library from one place to another. I am in the process of backing up the library on my 215J (NAS) to an external HD (plugged into a USB port on the 215J). I started this more than 24 hours ago and it is not yet half way through.

I haven't ever timed these operations with stopwatch in hand, but, from my experience, the software used is only one factor in determining the speed of transfer. For instance, I would normally expect USB to be faster than network transfers (there are exceptions, depending on the variety of USB (2 or 3) and network (10/100 or gigabit) in use). By far the fastest speeds in my setup are achieved with a directly connected USB3 drive, and I use gigabit networking throughout.

I'd guess that the Synology DSM copying routines are also a bit faster than anything run on Windows, because they are native to the NAS. I assume that, even for a NAS to NAS transfer, a Windows computer will need to work via SAMBA, which is the bit of the Linux operating system on the NAS which enables Windows-type file handling to work on the NAS. A large copying operation involves accessing lots and lots of files. Simon has a better handle on this than I do, but I'd guess that this slows things down.

You may well be right in your assessment that the initial bulk copy is best done using applications native to the NAS. However, once the copying process is started, it may be best to allow it to chunter on in the background until it is complete. Either way, as you say, Synctoy will come into its own when you want to be sure that all the changes you have made to the master library are exactly mirrored on the receiving device.

David