Freenas raid for 5 hard drives

Phill4321 · 16 Apr 2011 at 14:10

Hi, Ive currently built a freenas server with 5 x 2 TB hard drives. I was wondering what the best way to set these up would be. I am thinking a raid-5 configuration would be best. What are peoples thoughts on this? Also what would be the advantages of this in a raid-z format? And is there also a way to grow my raid setup and add more space to the pool. I can imagine my storage running out fast in a year to come.

Phill4321 · 16 Apr 2011 at 14:31

That sounds good. Is there a way to then add to more hard drives later down the line to the raid array and grow the pool of storage? This is a pretty big concern of mine to be honest.

Phill4321 · 16 Apr 2011 at 15:45

does anyone have an answer to the above?

Phill4321 · 16 Apr 2011 at 15:55

That is true I could use individual drives. I am setting this freenas box up so that I can rip my blu-rays to it and then share them around the house. I wanted to go the RAID route so that if one or two drives failed I would still have the data intact and I could replace the damaged drive depending on the raid level I was to use.

If I used separate drives, I would lose some of my data if one was to fail. I would also like to be able to use my drives as one pool rather than a few. My knowledge of raid arrays is very limited at best so please bare with me

Phill4321 · 16 Apr 2011 at 16:02

I also found this post on another forum, would this work?

What you are asking is not possible with traditional RAID5. For a very similar solution where growth IS possible, take a gander at ZFS (raidz1). What you do is the following:

1. Add disks and "format" them as zfs storage pool devices.
2. Create a virtual device (vdev) that combines your disks in single parity raidz1 (just like raid 5).
3. Add this vdev to a zpool which you can mount and use.

The vdev is your "array," and the zpool is a volume group of arrays/devices. In the future if you need to grow, you can add additional virtual devices to the zpool. You can also replace the disks of a vdev one at a time with larger disks. Both ways provide opportunities for expansion.

Things to keep in mind: ZFS is stable but still in development in Freenas 0.7. It runs better in a 64-bit environment, and can cause significant cpu overhead (similar to software raid5) as you add more devices to a vdev. ZFS vdevs can be files, slices of disks, whole disks, raid 5 groups, raid 6 groups, or mirrors, although the latter three are the only recommended setups for vdevs. Also, ZFS distributes data across the vdev members of a zpool, so if you had one vdev with raidz and another vdev with no parity/redundancy at all, data on your entire pool is vulnerable to failure of the second vdev. So it's important to maintain configurations with parity for any future vdevs that you add.

Some reading material for you: http://blogs.sun.com/bonwick/entry/raid_z
powerofpi

Phill4321 · 16 Apr 2011 at 18:17

I like that idea, I will probably get some 3tb hard drives in the near future and place them in my main computer, away from the freenas box. This way I can back the files up on the main computer and still have a backup that is separate from the server.

Phill4321 · 16 Apr 2011 at 19:24

Ive got a usb dock for hard drives that I could use, I could then back up my data once a week and leave the hard drives at my girlfriends in a rugged secure case. At least then my data will be off site and hopefully secure. Thanks very much for the help!