Update from above: the disk lights weren't on constantly, they were the opposite (inactive). I ended up restarting the computer to get control back from the "stopping" job

I thought I'd try a new backup to the cloud (amazon s3 deep archive), using the new format. It's only managed to backup 1.7GB in over 6 hours up a 4Mb/s link - I normally get much more than that.
It says 39 committed parts.
Even though I've enabled compression, the reported value after 6 hours is 0%.
Scanned 1524 files (3.6GB), file to backup 1523, processed 522 (1.73GB), uploaded (1.72GB).
The activity lights on the NAS box I'm backing up from seem to be on constantly.
The filepath of the file being backed up seems only to change every 15,20,30 minutes.
It's all very odd, and I dont' seem to be able to stop the backup plan, it's been "Stopping" for 5 minutes now.

Hi Sergey, many thanks for your prompt reply.

I guess my concern is that my main use is for long term offsite disaster recovery of my photos; I have about 1TB and add to this as days go by. I want to be able to continue to add to my backup for many years to come as I have new photos to back up. I'm currently re-uploading as support for (old) Amazon Glacier is said to being phased out and so I am re-uploading the whole TB to S3 Deep Archive before I lose the ability to add new images to Glacier. I don't really want to re-upload everything again in 2 years time if I cannot continue to add to my old format storage.

I still have the photos backed up in Glacier, so I could wait for the new format to come out of beta before I re-upload everything to S3 Deep Archive?

What would your suggestion be bearing in mind that the new file format is only in beta at the moment?

Thanks, Ian