Help needed 8 bay configuration

[tfast500]

Currently I have a Freenas server setup with 6 x 3tb WD reds in a raidz2

I am hoping to move this over to a new server that will have 8 bays. What should I do with the other 2 bays?

My first thought was to possibly rebuild whole server as an 8 x 3tb raidz2 but have since read that this is not an optimal configuration :? but still curious about using it anyways.

I started thinking that maybe I could just put the other two 3tb in a mirror configuration. What would this do to my current pool? performance ?reliability?

Would it be best to add this as a mirror in a separate pool instead? Possibly to store snapshots?

 

[gpsguy]

8 disks in RAIDz2 is fine. To "upgrade" from 6 disks to 8 disks, you'll need to backup your server, destroy the pool and start over with the 8 disks.

If you decided to use the other 2 bays for a mirror, don't stripe it into your current volume. If you want to stripe vdev's together, the additional vdev's should be the same width and type.

A bad example (often seen on the forum) is for someone to have a RAIDz2 volume and see that they've striped a single disk into the volume. Should that single disk fail, they lose the entire pool.

If you want to create a mirror, put them in a separate pool.

 

[nojohnny101]

what do you primarily use your server for?

 

[tfast500]

8 disks in RAIDz2 is fine. To "upgrade" from 6 disks to 8 disks, you'll need to backup your server, destroy the pool and start over with the 8 disks.

If you decided to use the other 2 bays for a mirror, don't stripe it into your current volume. If you want to stripe vdev's together, the additional vdev's should be the same width and type.

A bad example (often seen on the forum) is for someone to have a RAIDz2 volume and see that they've striped a single disk into the volume. Should that single disk fail, they lose the entire pool.

If you want to create a mirror, put them in a separate pool.

Thanks, I figured I would have to destroy the whole pool and basically start from scratch to go that route. Since I currently do not have enough reliable storage to backup everything, I am thinking this is not the route I will end up taking. Also, I am not ready to put in the man hours to get everything setup perfect again.

Since the addition will be a mirrored vdev losing one of the two additional drives would not cause me to lose the entire pool as long as at least one survives? Even if that is true I can see how this would defeat the redundancy of having raidz2 if it will only be a good as the weakest link (the new mirror vdev). Please correct me if i am thinking about this wrong.

what do you primarily use your server for?

Honestly it started as just a simple nas ~1tb of files, and the rest ~5tb of media for my plex. However now it hosts a minecraft server, virtual box, plex, plexpy, deluge, owncloud, codiad, and clonedeploy. Honestly nothing is business critical but I have put tons of days/hours into this thing. :) Yes mostly because I love to tinker.

 

[gpsguy]

Yes, you understand it correctly.

Since it will be a mirrored vdev losing one of the two additional drives would not cause me to lose the entire pool correct as long as at least one survives? Even if that is true I can see how this would defeat the redundancy of having raidz2 if it will only be a good as the weakest link (the new mirror vdev). Please correct me if i am thinking about this wrong.

 

[tfast500]

Yes, you understand it correctly.

Ok good thanks!

 

[nojohnny101]

Honestly it started as just a simple nas ~1tb of files, and the rest ~5tb of media for my plex. However now it hosts a minecraft server, virtual box, plex, plexpy, deluge, owncloud, codiad, and clonedeploy. Honestly nothing is business critical but I have put tons of days/hours into this thing. :) Yes mostly because I love to tinker.

Cool! Sounds like you're putting her to good use!

Since the addition will be a mirrored vdev losing one of the two additional drives would not cause me to lose the entire pool as long as at least one survives? Even if that is true I can see how this would defeat the redundancy of having raidz2 if it will only be a good as the weakest link (the new mirror vdev). Please correct me if i am thinking about this wrong.

Maybe. It depends if you create it as a separate pool or stripe it into your current pool. I would advocate for the latter so that if your mirror goes down, then you don't lose your existing raidz2. You'll just have a bit more to manage because everything won't be in one place (under one pool) but it sounds like you can handle that.

 

[Stux]

8 dive raidz2 is fine. Anything which says it is not "optimal" is out of date advise since ZFS now supports compression and has variable block sizes.

 

[CraigD]

I would get 2x3TB drives and rebuild a 8 drive RAIDz2 pool, others may move VMs and Jails to SSD mirror to speed them up, or add a large mirror for backup of your pool (Why have a backup in the same location?)

Snapshots mark the space unusable until they expire or are destroyed, they are not rewritten or moved, you can replicate them to another location however this takes time

If you can't back your current pool up maybe you should find a way to make this happen, Can a friend loan you some drives for temporary use? Even wait until you can buy some drives for backup. If you buy used drive be sure to test them...

If you do want to expand to an 8 drive RAIDz2 pool

Depending on your hardware it can be as simple as connecting SATA or SAS drives to data and power, they work fine outside of the case (you may have to power drives from another source, and temporarily add SATA/SAS card(s)

Create a new temporary pool duplicating to it, destroying your 6 drive RAIDz2, creating a new 8 drive RAIDz2 pool, duplicating from the temporary pool to your final pool, unmount the temporary pool

Since I currently do not have enough reliable storage to backup everything

I have put tons of days/hours into this thing.

If you need to expand your pool to 8 drives and don't want to lose all your work, you have to find additional storage, or you the time you invested will be lost

Have Fun

 

[tfast500]

I would get 2x3TB drives and rebuild a 8 drive RAIDz2 pool, others may move VMs and Jails to SSD mirror to speed them up, or add a large mirror for backup of your pool (Why have a backup in the same location?)

Snapshots mark the space unusable until they expire or are destroyed, they are not rewritten or moved, you can replicate them to another location however this takes time

If you can't back your current pool up maybe you should find a way to make this happen, Can a friend loan you some drives for temporary use? Even wait until you can buy some drives for backup. If you buy used drive be sure to test them...

If you do want to expand to an 8 drive RAIDz2 pool

Depending on your hardware it can be as simple as connecting SATA or SAS drives to data and power, they work fine outside of the case (you may have to power drives from another source, and temporarily add SATA/SAS card(s)

Create a new temporary pool duplicating to it, destroying your 6 drive RAIDz2, creating a new 8 drive RAIDz2 pool, duplicating from the temporary pool to your final pool, unmount the temporary pool




If you need to expand your pool to 8 drives and don't want to lose all your work, you have to find additional storage, or you the time you invested will be lost

Have Fun

Thanks, hmmm definitely something to think about. Now I'm thinking of going back this rout, though I just spent all my funds on a Dell R510. What is the best method to duplicate my current pool? I honestly haven't looked to far into backing it up yet. would I backup each dataset separate or is there a way to capture the whole pool? using dd or rsync?

 

[nojohnny101]

Thanks, hmmm definitely something to think about. Now I'm thinking of going back this rout, though I just spent all my funds on a Dell R510. What is the best method to duplicate my current pool? I honestly haven't looked to far into backing it up yet. would I backup each dataset separate or is there a way to capture the whole pool? using dd or rsync?

easiest way is replication. it is very simple and straightforward. it can capture the entire vdev which is what you want (make sure recursive is checked when you setup periodic snapshot!) this will keep everything intact. very good step by step instructions in the manual

 

[tfast500]

easiest way is replication. it is very simple and straightforward. it can capture the entire vdev which is what you want (make sure recursive is checked when you setup periodic snapshot!) this will keep everything intact. very good step by step instructions in the manual

Perfect! thanks for the link.