I am trying to extend my pool with smaller drives

[NasAficionado]

I have built only 2 machines running FreeNas in the last few years. My work with FreeNas is limited to "set it and forget it" type scenario.

I recently started shuffling the hard drives in the two machines (the second one had two spare 1TB hard drives doing nothing and I also took two spare 1TB HDDS from family members.

So I had 4 extra 1TB HDDs that I wanted to utilize and I used an existing PCI SATA card to shove them in the original FreeNas machine that already had (4) 2TB drives.

The original configuration was (4) 2TB drives configured as a Raid-Z (allows one drive to fail).

I attempted to "Extend" the pool but I have to configure those 1TB drives as Raid-Z as well in order to extend the size of the pool (which expands the total volume by 3TB). This seems a little risky given that the other drives are 2TB each and I don't know how the data will be striped between the eight drives... Will it recover if one of the 2 TB drives fail? And what happens if 2 of the 1TB drives fail at the same time?

I also attempted to create a vdev in Raid-Z2 (allows 2 drives to fail), which will expand the total volume by 2TB and add that vdev to the existing pool which will treat the new vdev as a separate 2TB hard drive.

But alas, looks like this option isn't possible because when I try to extend the pool with these drives I get this error:

"Adding data vdevs of different types is not supported. First vdev is a raidz, new vdev is raidz2."

I can also configure it as a separate pool and use it that way, but I prefer to have one large pool which allows me use all the drives.

Should I go ahead and configure it as Raid-Z? I am a little confused as to how the data gets split up between (4) 1 TB drives and (4) 2TB drives.

 

[styno]

It will just add the new vdev to the pool. Data that is on the original vdev will still be protected as before. Data that will land on the new vdev will be protected as well as you are about to use raidz on that one as well. It is however not possible to choose what data will land on what vdev and the pool will not automatically rebalance the existing data ( this is important if you are expanding for performance reasons, not so for capacity only setups. )

 

[NasAficionado]

I ended up using raidz and added the 1TB drives to the same pool. My main concern was more than one drive failing from the new set of (4) 1TB drives, but the chances of that happening are as likely as more than one drive failing from the old set. I don't know if having 8 drives instead of 4 drives makes the chances of that happening higher, but I will keep an eye on their health.

I am also in the process of repairing a 12 TB Raidz FreeNas that was an upgrade for this one. Once that one is up and running, it will be a secondary backup for the first FreeNas, until I build my ultimate rack-mounted FreeNas.

 

[Sparkey]

Most 1TB drives are pretty old. I wouldn't trust valuable data to one.

I recently ran out of space ion my pool. It was in a Supermicro SC825 which is an 8 drive chassis. I decided to expand it the right way. I backed up the pool and started from scratch with a Supermicro SC826 which is an 12 drive chassis. It was a lot more work than moving the current drives into a bigger chassis and adding vDev's but I've never really been comfortable with adding vDev's to an existing pool so for peace of mind I just started over. The new pool is Z2 with 59% free space so I should be covered for a while at least.

EDIT: Actually it's a 12 drive chassis but the pool is 11 drives with a hot spare.