Which backup method?

Fvbackup I meant 

Geez iPhone typos.  I don’t have another “nas” and ps shows dv backup running 

Dewdman42 wrote:

So I see that the file backup method is using a proprietary binary called fvbackup.  Anyone know if there is any information about what this binary does in terms of backup verification, incremental policies, etc.?

If you've chosen rsync as your backup protocol, then it runs rsync.  fvbackup handles scheduling, running of backup jobs from the web ui or backup button, etc.  

As far as snapshots go, "push" backups (source is local) create a temporary snapshot and then back up the snapshot.  "Pull" backups (source is remote) don't. 

FWIW, I use "pull" anyway, since my backup NAS are all on power schedules.  But I schedule the backups off-hours, so there shouldn't be anything writing to the NAS while the backup is running.

Are your questions specifically about ReadyDR, or in general.  The answers are different depending on the backup method.

For other than ReadyDR:

1. If the backed up device initiates the backup (a "push" backup, it starts by making a snapshot.  If the backup device initiates it (a "pull), then it doesn't.  But if the backup device is on a power schedule, a pull generally works better.  So, choose your poison.
2. The "Windows" backup uses time stamps.  Rsync is standard Linux rsync (so will work talking to your new NAS when you get it, assuming it's based on Linux), which uses it's own "quick check" algorithm.  You can Google for more details.
3. No, it does not do a verification.
4. Clearly refers to ReadyDR only.

For ReadyDR:

1. Ready DR only backs up snapshots.  And it doesn't make one on it's own, it uses your most recent one(s).  Keep that in mind when scheduling snapshots and backups.  It's Netgear's implementation of BTRFS send/receive.
2. It backs up as many snapshots as you tell it to.  You can have hourly snapshots and daily ReadyDR backups, and all new hourly snapshots will be backed up.  They are snapshots just like on the source system.  Where data isn't changed, each points to the same data.  It can keep them for longer or shorter than you have your main NAS set to do.
3. No verification beyond metadata safeguards built into BTRFS.
4. It's especially more efficient on some types of files.  As an example, I use it to back up my Veracrypt files.  Using rsync, a small change in the file will cause an entire new file to be backed up with rsync or Windows backup.  ReadyDR backs up only the changed data clusters.  Given one of them is approaching 1TB in size, that's a huge savings in time and backup space.  This holds true for any type of file where file changes don't move all the other data.  Databases are another specific place where it can help a lot, though I don't have any of any size where that's consequential.
5. A ReadyDR backup is not a usable share as it exists, as it is only a set of read-only snapshots (and must remain read-only).  To create a usable share, you need to "clone" it (just as with a snapshot on the source machine).  On the plus side, it being just snapshots is added protection against unitentional deletion and ransomware.  Likewise, the snapshots on the sending system must be read-only, so you cannot have "allow windows access" enabled (which, IMHO, is a really bad idea in all cases).  You can have "Allow Access to Windows Previous Versions" enabled, as Windows treats those as read-only.

I use a pull rsync backup initiated by my backup NAS for all shares except the one containing the VeraCrypt volumes.  But I have some pretty fixed "down time" where nothing should be changing on the primary NAS  I have a share just for the VeraCrypt files (and also because VeraCrypt slows to a crawl on writes if Strict Sync is enabled, so I've disabled it for that share).

So I see that the file backup method is using a proprietary binary called fvbackup.  Anyone know if there is any information about what this binary does in terms of backup verification, incremental policies, etc.?  I would presume it's doing all the same things that rsync does but I should not presume anything.  Just want to understand if this is still the best solution when backing up to local volume if it would be better in any way to use rsync, even to localhost.  I have another old readynas here I could also setup as a dedicated backup server, but its ultra 2 plus with only 1gb, probably I'd want to upgrade the ram to 2gb and upgrade it to OS6, etc..which might be worth the $20 to get that ram and have rsync backup to separate device, which is actually a slightly more safe 321 backup strategy..  So I am considering that, but on the other hand, I perceive that in the next couple years I will move to an entirely new NAS system, probably truenas but who knows...so..I am more keen to move on from my old readynas devices and just looking for simple interim solution, which I think its probably using USB drive plugged into my 524X and using the file backup method....simple...so long as the fvbackup program is doing everything I would expect it to be doing.

So the questions are 

1. does it create temporary snapshot to backup from?  I am guessing yes, but want confirmation
2. does it do incremental backups, and if so is it just based on filesystem timestamps or what is protocol?
3. does it do any verification of the backup itself, such as rsync -v does?  Any checksum checking?
4. is there anything more efficient about it compared to rsync?  
5. anything else to point out would be appreciated.

I think I have decided that readyDR is out at this time.  It would have been great back in the day with readyVault and all that.. powerful system, perhaps more efficient transfers...but its also quite proprietary and what if my readynas system goes totally down for some reason...I would not be able restore anything without obtaining a new readynas that support readyDR...so I am just leaving that out of the discussion now.