PVE-ZSYNC what does the 'dataset is busy' mean

[BuffaloBrent]

I've successfully setup PVE-zsync across 2 systems and turned the email notifications on. On what seems to be at random times, I get email messages stating that cannot receive incremental stream:dataset is busy It will successfully sync the next go-round.

Since this appears to be a temporary issue with that time's sync, I haven't paid too much attention to this. But I would like to know what exactly is going on when this happens. Can anyone please explain this error message in somewhat detail or point me to a reference to it? There doesn't seem to be any relevant references to this specific issue from what I've search for. I prefer to know what's going on with my systems, especially so I can 'ignore' these seemingly random emails, or have to dedicate some time to them.

 

[wolfgang]

Hi,

this means your dataset is currently busy with an operation.
Can you send the email output for more information.
I think you zfs is under heavy load and when the snapshot is created it takes time.
So it can't sync because the snapshot is not finalized.

 

[BuffaloBrent]

Here is the body of the email -

COMMAND:
ssh root@xxx.xxx.xxx.xxx -- zfs send -i CTUPool/vm-disks/vm-104-disk-1@rep_VM104_2016-07-20_06:30:21 -- CTUPool/vm-disks/vm-104-disk-1@rep_VM104_2016-07-20_06:45:02 | zfs recv -F -- CTUPool/vm-disks/vm-104-disk-1
GET ERROR:
cannot receive incremental stream: dataset is busy

Job --source xxx.xxx.xxx.xxx:104 --name VM104 got an ERROR!!!
ERROR Message:

I though that the snapshot referred to was created at the time of the sync. It appears that I'm wrong in that regard, which makes more sense now that I look at this closer.

Is there a way to determine the state of the snapshots upon request?

 

[wolfgang]

cannot receive incremental stream: dataset is busy

This means the send dataset is busy

though that the snapshot referred to was created at the time of the sync.

Yes on the receiver side but not on the sender side.

Is there a way to determine the state of the snapshots upon request?

AFIK there is no proper way.