BUILD Should I add more RAM?

[Stux]

You replicate the snapshots from primary to secondary

I'm not snapshotting my secondary separately yet, but I guess I could

 

[Matt Tyree]

Gotcha. So just kinda part of the mirroring process. Cool!

(Man, this thread has rabbit-trailed like crazy!) :-D

 

[Stux]

Gotcha. So just kinda part of the mirroring process. Cool!

(Man, this thread has rabbit-trailed like crazy!) :-D

Replication. Not mirroring :)

Mirroring is what happens to drives in a mirror. And that implies that all writes are instantly replicated. They aren't. There has to be a snapshot, and then the snapshot is replicated on the other system (as a delta relative to the most recent common snapshot)

One of the neat things with ZFS is that snapshots are instant, and the delta calculation is very quick, unlike say, rsync across a complicated set of data.

 

[Matt Tyree]

Yeah, I saw after reading up some on replication that it uses the snapshots.
I'm just coming from a more manual angle. I'm used to using my SyncBackPro software to handle moving all the files around, mirroring (one of the ops in the software is named "mirror"). That's what I was planning to do with the two FreeNAS boxes: Mirror the main NAS to the offsite one via ftp (sftp or ftps). But, there's obviously a better way with FreeNAS via replication. I just don't know squat about it yet. :-D

This thread has gotten way off-topic...
With replication, do the two boxes have to have the same amount of storage? The offsite box was just going to use my previous USB backup drives: two 4TB WD Greens and two 2TB WD Greens. This would accomodate all of the data for the moment, but my local NAS can hold much more.

 

[nojohnny101]

With replication, do the two boxes have to have the same amount of storage?

They do not.

 

[Matt Tyree]

They do not.

Excellent. And would you put the two 4TB drives and two 2TB drives into one big pool or separate them into pairs?
Not sure how much space the replication takes. Would a mirrored 6TB (assuming it could work that way) be better than a mirrored 4 and 2?

 

[Stux]

Excellent. And would you put the two 4TB drives and two 2TB drives into one big pool or separate them into pairs?
Not sure how much space the replication takes. Would a mirrored 6TB (assuming it could work that way) be better than a mirrored 4 and 2?

Can't work that way, but a mirrored 4 & 2 will give you 6TB of storage.

That means you can store/replicate about 80-90% of 6TB of compressed data (circa)

So it depends on how well your data compresses how much data you can store.

 

[Dice]

how much data you can store.

..and how much you really need to store in the 2nd tier.

 

[Matt Tyree]

..and how much you really need to store in the 2nd tier.

Yeah, there are definitely some things that will be on the main NAS that aren't the end of the world if it were lost due to something catastrophic.