Adding new drive

[Janus_006]

Hi,

I'm curently planning to move my CentOS/mdadm/RAID5 data to a FreeNAS ZFS. I'm new in ZFS. Here is my plan and my setup.
- I have curently 3x3Tb RAID 5 on mdadm.
- I was able to move half of data on temporary storage; but 2.7 Tb remaining. I just bought a new 3Tb drive.

My initial plan was to copy the 2.7Tb to my new drive, clean my RAID5 and built the new setup in a ZFS.
After copying all data on the ZFS, include my new/temporary drive to the ZFS, as we can do in RAID5.

But, as I was reading, it's not possible ? Can you confirm ?As I can understand, to increase the space of ZFS, I must create a new VDEV with my new drive. But this new VDEV, with only one drive, will not be redundant.

Am I understood corectly ? Any way to add a fourth drive to my system ?

Thnaks for your help,

 

[PhiloEpisteme]

I'm curently planning to move my CentOS/mdadm/RAID5 data to a FreeNAS ZFS. I'm new in ZFS. Here is my plan and my setup.

Welcome to FreeNAS! To get started I suggest you go through some of the resources and user guide if you haven't already done so. It would be a good idea to understand the benefits and limitations of FreeNAS and how to effectively design pools and vdevs. If you post your desired use-case, hardware, and general budget to the Will It FreeNAS board folks around here are happy to help offer some advice etc.

As I can understand, to increase the space of ZFS, I must create a new VDEV with my new drive. But this new VDEV, with only one drive, will not be redundant.

This is correct. The way to grow a pool in FreeNAS is to add a new vdev. You lose your pool if you lose a single vdev. If you have a vdev which has no redundancy your pool will be quite vulnerable.

My initial plan was to copy the 2.7Tb to my new drive, clean my RAID5 and built the new setup in a ZFS.

Keep in mind that there are folks who advice against the use of single-drive redundancy such as RAID5 or ZFS's analog, RAIDZ1. The reason is that when you lose one of your drives and go through the process of resilvering the drive there is no parity data. You are vulnerable to read errors currupting your data and if a second drive fails during resilvering you would lose the whole vdev and thus your pool. Many folks suggest using RAIDZ2 which tolerates two drive failures and during resilvering during to a single drive failure you still have parity information against which errors can be checked.

FreeNAS is very good at keeping your data safe if you design it correctly. Before you commit to a pool layout etc I suggest you check in on the forums for feedback and advice. It can help prevent understandable mistakes that may leave your data vulnerable.

 

[melloa]

But, as I was reading,

First of all, welcome and thanks for reading the information in here.

What is your current configuration, so people can better provide suggestions?

Ops ... @PhiloEpisteme was faster in replying ;)