What are some common reasons a pool fails?

[Rusky]

I'm trying to figure out how to split up my drive configuration and seeing if it's worth it to create a separate pool for backup

I have 6x 500gb drives

I keep about 250gb backup and the rest is media

I was thinking a mirror pool with 2 drives for backups and the rest a raidz2...thoughts?

 

[Anthony Chastain]

Having a 'backup' in the same system as your live data doesn't really make much sense.

There are several reasons you might want a backup.

1. Drive failure. This is mitigating using Raidz2 and Raidz3 as you have suggested.
2. Data corruption. This is mitigated by scrubbing (and having ECC RAM)
3. Data manipulation errors (accidental deletes/overwrites, etc.) This can be mitigated using snapshots.
4. Total loss of server (fire, flood, catastrophe, etc.) This is why you really need a true backup. It should be off-site or at the very least as far away from the live server as possible.

My recommendation would be to use all your drives in a Raidz2 or Raidz3 configuration (Raidz3 would be safer than Raidz2) and forget storing in the same system twice. Then I would look into something like Amazon Web Services (AWS) and the s3cmd command for an actual backup of your data. AWS will host static data in 'Glacier' at $4 / Month / TB.

 

[Rusky]

This is purely for personal use and mainly for media storage but I just wanted to move the hard drive I use for backup outside my primary desktop.

I think I'll go with the z3 since that'll give me the most reliability and I'll still have more than enough space left over.

I use offsite backup for smaller data that's more important to me.

 

[NASbox]

This is purely for personal use and mainly for media storage but I just wanted to move the hard drive I use for backup outside my primary desktop.

I think I'll go with the z3 since that'll give me the most reliability and I'll still have more than enough space left over.

I use offsite backup for smaller data that's more important to me.

I agree with @Anthony Chastain on one pool... There is a handy space calculator here that will show you the impact of your choices:

https://jsfiddle.net/Biduleohm/paq5u7z5/1/embedded/result/

Have you bought your drives yet? If not, make sure you get drives from different batches (different manufacture dates), and burn them in well. (There are resources on this board-just search).

Those drives are pretty small, and should re-silver fairly quickly in the event of a failure. Unless your stuff is REALLY critical or you get into really big drives, I would think RAID-Z2 should be quite safe. I'm running 8x6TB on RAID-Z2.

If you haven't chosen a case yet, you might want to get one that will give you an open 5-1/4 Inch drive bay. If you have a spare SATA port, you can then create a hot swap backup. I bought some removable cartridges from Addonics, and they have been doing a very nice job. I can push 8TB out to a large single drive pool overnight for an offsite backup. You wouldn't need such a big drive because your main pool is much smaller.

I don't know what your Internet upload speed is like, but unless you have a very fast service it is going to take a very long time to push 1TB up to AWS. Then if you do need to recover, how long is it going to take to get your data back?

Just some thoughts to consider... your needs / budget will dictate your decisions.

Good luck.

 

[Rusky]

These are all really good points and gives me lots to ponder over.

I already have 9x 500gb drives laying around...but that's a REALLY good idea to check if they're from different batches.

The desktop I'm using is an HP z420, Xeon E5 1620 v3 8 core processor, 16gb ram

The desktop holds 6 drives but I'm actually thinking of powering off 2 of the drives and leaving 4 in a Raid-Z2 that way if a drive fails all I need to do is power on the spare and let it sync up.

Once the pool is create, am I able to add a drive to it and expand the space?

 

[gpsguy]

Once the pool is create, am I able to add a drive to it and expand the space?

You can add additional vdev's to the pool, but you can't add an additional drive to your existing RAIDZ2 vdev.

 

[danb35]

Once the pool is create, am I able to add a drive to it and expand the space?

No, not safely.

 

[Rusky]

2 people with a hard no...welp I'm glad I asked first.

Thanks!

 

[NASbox]

With your system I would recommend you use all 6 drives. It is really nothe hard to power down and swap a drive.

Use the space calculator to see the difference in space BEFORE you create your pool. Having just gone though the exercise of 4xRAID-Z2, 2xRAID-Z1 to 8xRAID-Z2 I can tell you that it is no fun. You have to destroy your pool and hope you have done your backups right and the media doesn't fail!

 

[Rusky]

I was thinking about saving money on my electric bill by not running the extra drives but I used a power usage calc and it only really comes out to $15/year so def not worth the hassle of rebuilding the pool.

In case anyone is interested this is the calc I used
https://outervision.com/power-supply-calculator

 

[rs225]

Go with raidz2, and use the extra drive for more offsite backups of your important stuff. Everything that is not backed up, shall eventually be lost.