Replication failed in network mode about znapzend HOT 6 CLOSED

dumb question: you have 4 backup plans which run at the same schedule. do you use different mbuffer ports for all of them on the destination?

from znapzend.

Yes, the same port.
Is it wrong?
May be i've misunderstand the idea of network mode. But how should i configure four backupsets?

from znapzend.

well, if you use network mode there will be a direct tcp connection from the sending zfs to the mbuffer on the remote host. if you have different backup sets which run at the same schedule (in your case 4) they all try to send to the same mbuffer instance at the same time and will fail as the first mbuffer process is already attached to an individual receive zfs process...

either you set up all your datasets you want to backup in a common base dataset and then create a recursive backup plan for the base dataset or you keep your 4 individual backup plans but specify a different mbuffer port for each of them (i.e. each send/receive gets its own mbuffer process).

from znapzend.

Thank you, hadfl.
I hoped znapzend sends snapshots one by one. But it doesn't. Ok.

Now i see your suggestions, but have to notice. It's quite too hard, guess not only for me, to compose recursive backupset - not every inner dataset should be backed up. And setting up different ports has issue too - to achieve max speed it's necessary to setup buffer size not less 1Gb. It's easy to eat all off destination RAM. :-)
It seems, my way - is using SSH. Maybe, according to its low speed and big amount of initial data, doing initial transfer via mbuffer, then switching to ssh.

from znapzend.

znapzend only works sequential for recursive backups. all other backups run in parallel.

you can always delay a send/receive by configuring post-snap-command=/usr/bin/sleep <seconds> and so stagger your send/receive processes (snapshots will still be done at the same time). however if one send/receive will take more time than the delay it'll fail again if using network mode and the same mbuffer port...

edit: there might be a future option to define a recursive backup plan (recursive snapshots) but to exclude datasets from being sent to destinations...

from znapzend.

Yes, sure. Now it's clear. Thank you, hadfl!

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