TrueNAS repication fail-over/fail back - how does it work?

[Roman King]

Hello dear ALL
I am a TrueNAS newbie and I am looking for some answers. Probably here I can find what I am looking for.
We have purchased two TrueNAS Enterprise devices, but they are still sitting in the boxes, so I am trying to learn the TrueNAS world using two VMs.
I have experience working with NetApp FAS and Dell FluidFS, so I hope TrueNAS will not be totally different.
My questions are replication process-related.
We are planning to have two sites (main and DR) and replicate NAS data (CIFS/NFS) between them.
So, I will have about 300 shares-exports.
I will have one disks pool.
Here is question #1
Should I create datasets per each share, or does some best practice scenario exist? Like, create a new dataset for CIFSs, and cut shares from there?

Question #2.
I have found that replication is working from dataset A to B only in case dataset B is Read Only.
Let's assume the main site is down, and I manually change DNS settings to point to my DR site. All clients will access the same \\myTrueNAS but the DR one, correct?
BUT this device is read-only!
Probably, I will be able to build a script that clears RO attributes from all volumes.
And, let's assume, during the next two weeks users will be using the DR TueNAS device (the main site is totally demolished).
Then, the main TrueNAS is up and running. What are my steps to failback? The only way I see is to set up replication from B to A, making A read-only. BUT I have a lot of users, connected to NAS 24/7, so, technically, I can't failback.
Or I do? Please describe.

Thank you very much in advance

 

[NugentS]

HA only works with an enterprise license. So this will only work properly using the physical hardware your have bought from IX.
And as I have no idea how it works - try testing with that kit rather than VM's. You can't break it physically and as you have the kit - it better to play with the actual kit, before putting it in production

 

[Roman King]

HA only works with an enterprise license. So this will only work properly using the physical hardware your have bought from IX.

Hi

You're talking about HA which is "two heads sharing the same set of disks"

I am talking about the replication between two physical hosts (with HA)

 

[Roman King]

It seems like TrueNAS Scale will do what I am looking for, but there is no GA date for this feature

 

[NugentS]

No I am not. HA is not (to my knowledge) 2 heads, one set of disks. Its 2 NAS's with the same data

Note I do not have an enterprise license

 

[sretalla]

Have a look at the Lawrence systems video on truenas failover... you're wasting your time trying to invent what you think it should be and make the non-enterprise system do that.

TrueNAS M50 High Availability (HA) - Failover Demo by Lawrence Systems

More information on TrueNAS M50: https://www.truenas.com/m-series/Lawrence Systems: https://www.youtube.com/user/TheTecknowledgeDon't forget to follow us on ...

www.youtube.com

 

[Roman King]

This is what Lawrence explains:

TrueNAS High-Availability (HA) Explained | TrueNAS - Welcome to the Open Storage Era

I am often asked if the two storage controllers in a TrueNAS high availability configuration are active/active or active/passive. They’re neither. They’re

www.ixsystems.com

I am often asked if the two storage controllers in a TrueNAS high availability configuration are active/active or active/passive. They’re neither. They’re “active/standby.” Allow me to explain the difference.
In the case of an active/passive and active/standby disk array, when a LUN is created it is presented to a host server via a primary storage controller and all data I/O for that individual LUN is transmitted and received via that controller. The secondary storage controller awaits the authority to take ownership of the LUN if a controller or storage network path failover is invoked. Once failover is invoked, the secondary storage controller assumes control of the LUN and facilitates all reads and writes until control is passed back to the original storage controller.

TrueNAS M50 High Availability (HA) - Failover Demo by Lawrence Systems

More information on TrueNAS M50: https://www.truenas.com/m-series/Lawrence Systems: https://www.youtube.com/user/TheTecknowledgeDon't forget to follow us on ...

youtu.be

And here is the main sentence:

TrueNAS M50 High Availability (HA) - Failover Demo by Lawrence Systems

More information on TrueNAS M50: https://www.truenas.com/m-series/Lawrence Systems: https://www.youtube.com/user/TheTecknowledgeDon't forget to follow us on ...

youtu.be

So, Lawrence is talking about two heads (ok, two motherboards with controllers) attached to the same set of disks.
He is NOT talking about two TrueNASes in different buildings!

 

[Roman King]

And this actually proves my words:

TrueNAS M50 High Availability (HA) - Failover Demo by Lawrence Systems

More information on TrueNAS M50: https://www.truenas.com/m-series/Lawrence Systems: https://www.youtube.com/user/TheTecknowledgeDon't forget to follow us on ...

www.youtube.com

 

[NugentS]

Teach me for making assumptions about what HA was