Is my data safe now?

[devnullius]

I started to worry after reading this PDF https://forums.freenas.org/index.ph...ning-vdev-zpool-zil-and-l2arc-for-noobs.7775/

I assumed that, with 3x 3TB ZFS volume, I'd be safe if a disc crashed. And that it would be no problem to add / remove discs as I feel (1 at a time, of course).

Is that correct? Volume status shows: DiscSet > raidz1-0 (da1p2 + da2p2 + da0p2) with inherit (lz4).

 

[gpsguy]

While you are safe if a disk crashes, if a second one fails while you are replacing/resilvering a drive, all is lost. That's why we recommend RAIDz2 these days.

Unfortunately, you can't add additional disks to the existing vdev (other than a mirror), after the fact. You can stripe additional vdev's, for example add another 3x3TB RAIDz1 vdev to your pool. But, again we don't recommend it for the big disks of today. Now, if you have adequate backups, RAIDz1 might be fine.

If you wanted to change to say RAIDz2, you'd need to backup your existing pool and start over.

 

[Mirfster]

You're supposed to read all that stuff before setting up FreeNas... ;)

 

[devnullius]

Ok, if I'm gonna setup FreeNAS next time, what choices should I make / look for? I want as much flexibility as possible and a lot of redundancy (depending on space 'lost')...

Thanks :)

 

[devnullius]

Your supposed to read all that stuff before setting up FreeNas... ;)

You're*

 

[Mirfster]

You're*

Fixed. Got me.

 

[nightshade00013]

Ok, if I'm gonna setup FreeNAS next time, what choices should I make / look for? I want as much flexibility as possible and a lot of redundancy (depending on space 'lost')...

Thanks :)

That is a decision you have to make for yourself. I went with a 7 drive raidZ3 for two reasons. One is that when I add a second vDev I don't want to have the risk of two drives failing in one and lose the whole pool and two at some point in time when larger disks are available cheaply and I end up swapping from 4TB to say 8 or 10TB I will have the needed redundancy. From my understanding raidZ2 is good through 6TB but after that it starts to have the same possible problems as raidZ1 did when we got into drives larger than 2TB. I have the desire to have a system that was as low cost as possible (minus the drives) but would be viable for an extended period of time.

If you are building a system that will be a stopgap till you can build a better and more modern one you will make different decisions based on your current and expected future needs. With that said however 3TB drives should be placed into a raidZ2 as was said earlier and most people use at least 6 drives since 2 will be effectively lost to redundancy. You can do it with 3 but will only have one drive worth of capacity so you also have to plan for your data expansion needs. You can add multiple vDev's or swap drives to increase capacity but the decisions you make now will affect how your expansions take place or will require you to create a backup of some type and rebuild your pool. There are a multitude of combinations beyond that as well so the best thing you can do is research and ask a few questions.

On a side note the more information that you give us about your plans the more we can help with your plans. A vague questions begets a vague answer.

You're*

Their, there, they're, it'll be ok.

 

[devnullius]

This should help me (and others) on they're way :phttps://jsfiddle.net/Biduleohm/paq5u7z5/1/embedded/result/ Zx-calculator

Thing I still have to figure out: does every volume always contain a fixed amount of disks? Or is there tech where I can add or remove disks (following a supported procedure as to re-allocate all recovery data and data itself) as I please.

Peace!

:) Devvie

 

[danb35]

does every volume always contain a fixed amount of disks?

Every vdev always contains a fixed number of disks, except that you can add disks as mirrors and remove disks from mirrors. You can turn a single-disk vdev into a two-disk mirror, a two-disk mirror into a three-disk mirror, or a three-disk mirror into a two-disk mirror. You cannot change the number of disks in a RAIDZn vdev. You can add vdevs to a pool at will, but once a vdev is added to a pool, it can never be removed. @cyberjock's PDF (I think it's the top sticky in this forum) has more detail.