How to run multiple backups simultaneously?

[rexjones]

I have 2 internal drives and 2 externals, and I would like to backup internal#1 to external#1, and internal#2 to external#2. Is there a way to run both of these tasks simultaneously?

I have tested it by just opening 2 instances of FreeFileSync, but I'm not sure if that will cause any issues or if it is intended to be used in that way.

[Zenju]

Running two instances at the same time is fine and also should speed up the synchronization, provided that all four drives can process I/O independently from each other.

[rexjones]

Thanks for the reply. Actually, would it be simpler to just run it as shown in this attachment?

C - boot drive with some data
D - data drive
E - smaller drive with misc stuff

F - external drive #1
G - external drive #2

I think I was a little confused yesterday because I didn't realize that each input folder could have its own separate output folder. So would running it like this negate the need for running separate instances, or would you still recommend running 2 instances and having C->F in one, and D->G and E->G in the other?

[Zenju]

I would just test it. Depending on where the bottleneck is, it might be faster to run three instances (e.g. ffs_batch jobs) at the same time, than one instance with three folder pairs.

[rexjones]

And just to make sure, it is safe to backup the entire boot drive while it is running?

[Zenju]

Sure, whether copying will work for system files is a different question, though.

[rexjones]

Yeah I got errors on some of the system files but everything else was fine. I did get this error right at the start though:

Cannot set directory lock for C:\.
Cannot write file C:\sync.ffs_lock.
Error Code 5: Access is denied. (CreateFile)

But aside from that, everything transferred perfectly. Great software, will definitely be using this for all my backups from now on. Thanks for the help