Rsync for idiots: old server to new


Mar 9, 2024
Hi. New forum member, but not new to TrueNAS or to servers. I've been building and running networks since the end of the 1980s.

I have got 2 home TrueNAS Core servers, both running on HP Microservers. Both have 4 SATA drives in ZRAID, with a single shared pool, both have 8GB RAM. Both are sharing that pool over SMB to a mixture of Linux laptops, Macs, and very occasionally to Windows 10 or 11.

The old server is a Microserver N54L, with 4 x 2TB drives. It is 97% full. It has TrueNAS Core 12.


One share:

Name: share
Path: /mnt/vol0/share
Enabled: yes

The new server is a Microserver Gen 8, with 4 x 3TB drives. It is almost empty. It has TrueNAS Core 13.


I want to rsync everything on the main share to the share on the new server.

Then, my plan is to upgrade the old one from 12 to 13 and try to dedupe the data, but I want a full backup *first*.

I don't own a drive big enough to do a disk copy.

I have enabled the rsync service, obviously.

I have tried setting up a task to do this, first on old syncing to new, then when that failed, on new syncing from old. Both failed. I deleted them. This was months ago and I have not kept any logs.

I did try asking on Reddit /r/truenas, but got a very hostile response. :-(

Where should I begin? I normally use rsync only locally, from one drive to another on the same machine.


Mar 9, 2024
Additional info: no VMs. No appliances. Internal home LAN, no other servers, no internal DNS or anything.

One TimeMachine share on each server. On the new server, in a separate dataset. (I have only been using ZFS for about 4 years and it is not clear to me what a "dataset" is yet. I configured it with a new one as that was the only way to get TimeMachine to work on TrueNAS Core 13.) I do not wish to sync the TimeMachines or their contents.


May 17, 2014
You posted in the TrueNAS SCALE sub-forums, so I am requesting a moderator move your post to the Core sub-forums.

First, read up on De-Dup;
It is not meant to stop you, but to open your eyes to the limitations.

That said, late this year a "fast de-dup" is expected to be released that improves ZFS De-Dup performance noticeably. As well as add some tunables to tweak a specific instance of fast de-dup for various uses. (Of course, some people don't want to use a new feature on first release. They may want to wait for the "bug" release. Or even several releases after.)

Next, a "dataset" is like a file system. You can setup attributes for the "dataset" like you would for a file system. You should never use the top level "dataset" that is named after the pool. (Well, their are exceptions to every rule... but most users are not the exception.)

Last, if the intent is to copy a dataset or group of datasets from one instance of TrueNAS to another, then ZFS Replication using Send and Receive may be a better option.

Now back to your question of RSync. Their are 3 ways to run RSync:
  • To or from a RSync daemon
  • To or from a local file system
  • To or from a remote login, like with SSH
I tend to use which ever is appropriate for the task. For a one off, it it may be easier to use the 3rd option with SSH. But, if performance is lacking, using the 1st option is fastest. (And security should not mater on a local network...)

As for the details, I don't have time tonight to dig into it, perhaps someone else will.