ZFS send - moving data question

[danzi]

Hi All,

I have NAS A with 2x 1.5Tb mirror and NAS B with 2x 2Tb new disks. I'd like to move the data between them from NAS A to NAS B using zfs send/receive. For this I created a snapshot on NAS A which is now referencing ~700 gigs of data.

Q:can I receive the data on NAS B to a specific dataset that has different feature flags - e.g. compression is on?

Any other suggestions to move the data also welcome - e.g. configure NAS B as preferred and then move the data manually also an option, but wanted to take advantage of ZFS's send/receive feature

Thank you
D.

[Onichan]

Pretty sure that's not possible.

Technically you could create a new dataset on the NAS B with compression on then zfs receive the source dataset and pipe it directly to a file within the new dataset. That would technically compress the source dataset, but it would be just a large stream dump and not really useful unless you wanted to directly restore it somewhere else at a later date.

Only real option is create a new dataset with compression on, cp all the data over to the new dataset and delete the old one.

[Princo]

It is possible, simple and easy.

First: set the desired attributes on the receiving Pool.

Example (assuming "tank" as the name of the receiving Pool):

Code: Select all

zfs set compression=lz4 tank

Then:

On the sending site (i am using netcat instead of ssh, bc it is faster):

Code: Select all

zfs send $YOURSNAPSHOT | nc -w 5 $IP_OF_NAS_B 9000

On the receiving site:

Code: Select all

nc -l 9000 | zfs receive -vdF tank

You had to replace $YOURSNAPSHOT and $IP_OF_NAS_B with your own values, and you have to adapt the name of the receiving pool.

Caution: you MUST NOT use the parameter "zfs send -R"!!!

Greetings
Princo

[Onichan]

I thought zfs send retained all it's properties, looked into it more and it looks you're right https://docs.oracle.com/cd/E53394_01/ht ... gbchx.html.