Help with deciding configuration (2x4TB, 1x5TB)

[di0de]

My system is the Lenovo TS140, 3.4 GHz i3, 16GB ECC RAM. I just purchased two 4TB WD Reds, and all my data is currently on a single 5TB drive. Now I'm trying to figure out the best way to configure my storage. I read through Cyberjock's powerpoint, and numerous threads to get some information. Here's what I'm thinking of my options:

1. Create a vdev(RAID0) with the two 4TB reds in a new zpool configuration. Transfer my data to this, then create a new zpool from the 5TB to be used for backup.

2. Create a vdev(raidZ) with all three drives, and rely on email alerts (and scrubs/smart tests) to notify me of possible drive failure. In which case, I overnight a new drive to replace the one in question.

I am leaning towards option 1 because I have a guaranteed backup that won't be affected should one of my vdev's fail. I'm a little nervous of putting all my eggs in one basket with option 2. Also, I'm not confident in the long-term lifespan of my 5TB (I pulled it from a seagate expansion external, and its a couple years old).

I've done my best to understand vdev's, zpool's, and RAID's, but clearly I don't have a lot of experience. I appreciate any thoughts on my options or even a different suggestion if you have one. Sadly, buying new disks isn't an option for my right now (except in the case of an emergency). If I forgot to add something, I will. Thank you!

 

[Robert Trevellyan]

buying new disks isn't an option for my right now

If you have no place to move your data temporarily, then option 2 is off the table and option 1 is the only way to go. In ZFS terminology, you'd have one pool built from a 2-drive mirror vdev and one pool built from a single-drive stripe vdev.

If you have a place to move your data temporarily, you could do option 2, but in this case you'd be much better off buying one more 4TB drive and building a 4-drive RAIDZ2 pool. You'd have to switch to manual mode when creating a volume using drives of different sizes (3x 4TB and 1x 5TB).

 

[di0de]

Oops, didn't even occur to me that I wouldn't be able to offload my data for option 2 anyway. Thanks for the quick response, I think I'll move forward with my 2 drive mirror vdev and single drive stripe. Is it bad practice to have more than one zpool? In other words, is there any reason I shouldn't move forward with this configuration?

 

[depasseg]

Is it bad practice to have more than one zpool? In other words, is there any reason I shouldn't move forward with this configuration?

No reason not to do it. I have something setup like that.

 

[di0de]

Thanks again!