ZFS replication VS RSync

[--JMS--]

Hello all,

My aim is to ensure that 2 NAS are always synchronized (same data on both NAS).
I plan to have one volume for the OS and another one for data storage, on each NAS.

Then, let say that NAS#1 is the “master” and NAS#2 in the “slave”. My aim is to have NAS#1 send data over Ethernet (local GbE network) to NAS#2 in order to always have a copy/clone of NAS#1’s data. The storage capacity of each NAS is (only) 1 TB.

So I notice through the forum that I have 2 choices :
Rsync task
ZFS replication

But I don’t really understand the main difference between these 2 options?
To me, each of them are some kind of scheduled task. I read that rsync is not indicated in case of big size transfer, is that correct?
Could I get “real time” copy ? in other word, is that possible that NAS#1 send new recorded data to NAS#2 as soon as data are written on NAS#1 storage volume?
As sais previously, the storage capacity is 1 TB. The size of new files to be written to NAS#2 is about some GB.

I don’t find the answer to these question on the board and/or on google :/
I hope you could help me ! ☺

Let me know if you need further information, or if I miss something.

Thanks in advance for your help,
Regards,
JMS

 

[cyberjock]

You are correct, they are not real-time copying. The best you could hope for would be a regularly scheduled task of some short time frame(don't make it too frequent) and let it replicate over as necessary. ZFS snapshots are FAR faster if you plan to do short time frame copying to the backup server.

There is no real-time copying. If you have a need for a backup in real-time about the closest you are going to get is a pool with ZFS mirror vdevs. Even then, its not a "true" backup.

 

[--JMS--]

thank you for this answer.
So I'll go with ZFS replication. I'll let you know if I encounter issues :)

 

[Thomas BS]

Hi JMS,

I am having some problem with ZFS replication and would like to ask some information about your scenario and your experiences.

My scenario:
- work on Box 1 (FreeNAS 9.2). Switch it on when I need it. (Home Office). Might be switched off at least during the night and vacation days.
- use Box 2 (FreeNAS 9.2) as automatic "mirror". Each time both boxes are switched on, the changes from box 1 should be "replicated" to box 2

I am using ZFS replication which works fine as long as both boxes are switched on.

When I work on box 1 and box 2 is turned off, ZFS replication was starting with the next snapshot on box 1 if box 2 was reachable (tuned on). That was working for a few times. One day it stopped and the next replication attempts always failed with "broken pipe" messages. I guess the broken pipe appears when I switch off box 2 while box 1 replication task has not been completed.

My question:
Did you experience "broken pipe" failures as well and how did you fix them?

Thanks !

Thomas