New Install; Maximise storage (8x18TB)?

[bluegandalf]

Hi everyone,

I am currently running OpenMediaVault in a Raid5 config with 4x18TB drives, with no backups (I know, I know - It's data I am okay with losing but would rather not).
I have another 4x18TB clean drives available, currently, with me.

I am about to install TrueNAS Scale and move to the ZFS system but wanted a sense check + some advice? on how to do this best.

1. I will transfer my current data(~42TB) onto the new 18TB drives (using 3 of them - no RAID, nothing, simple copy for transferring)
2. Install TrueNAS Scale and add the 1 new 18TB drive to create a 5x18TB RaidZ2 pool giving me about 54TB of usable space.
3. Move all data from the 3 drives to the ZFS Pool.
4. Create a separate pool from the now cleared 3 drives in RaidZ1.
5. Wait for the RaidZ expansion feature to release (any guesses when?) and then destroy the 3x18TB RaidZ1 pool and expand the existing vdev to 8x18TB RaidZ2.

Any issues or bottlenecks you foresee? Any thoughts on how to do this better?

 

[ChrisRJ]

The interim RAIDZ1 pool does not make sense to me with my current understanding of your approach. Where would you store its contents until the main pool expansion is done?

 

[MrGuvernment]

Hate to think if one drive fails how long a rebuild is going to take....

 

[bluegandalf]

The interim RAIDZ1 pool does not make sense to me with my current understanding of your approach. Where would you store its contents until the main pool expansion is done?

That's true. Hadn't considered that. Is there anything I can do in the interim?

 

[Arwen]

Hi everyone,

I am currently running OpenMediaVault in a Raid5 config with 4x18TB drives, with no backups (I know, I know - It's data I am okay with losing but would rather not).
I have another 4x18TB clean drives available, currently, with me.

I am about to install TrueNAS Scale and move to the ZFS system but wanted a sense check + some advice? on how to do this best.

1. I will transfer my current data(~42TB) onto the new 18TB drives (using 3 of them - no RAID, nothing, simple copy for transferring)
2. Install TrueNAS Scale and add the 1 new 18TB drive to create a 5x18TB RaidZ2 pool giving me about 54TB of usable space.
3. Move all data from the 3 drives to the ZFS Pool.
4. Create a separate pool from the now cleared 3 drives in RaidZ1.
5. Wait for the RaidZ expansion feature to release (any guesses when?) and then destroy the 3x18TB RaidZ1 pool and expand the existing vdev to 8x18TB RaidZ2.

Any issues or bottlenecks you foresee? Any thoughts on how to do this better?

In theory, you can create a 7 disk RAID-Z2, using 5 real disks and 2 x sparse, (aka fake), disks. This is without any redundancy, until you have the data copied over. Then, using 2 of the remaining 3 disks, you replace the sparse / fake disks, (one at a time), to get your redundancy. Later, when RAID-Zx expansion becomes available, expand by the 1 remaining disk.

This is not for the faint of heart, and has the potential to blow up big, as in nuclear big.

The old adage applies in this case: If you have to ask questions, you probably shouldn't do it.

Creating a degraded pool

WARNING: HERE BE DRAGONS. IF YOU DON'T KNOW EXACTLY WHAT YOU'RE DOING, DO NOT FOLLOW THESE INSTRUCTIONS. IN FACT, IF YOU NEED THESE INSTRUCTIONS, YOU PROBABLY SHOULDN'T FOLLOW THEM. There are a few cases where it may make sense to create a...

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