Agree on that Luca, the performance during rebuild is not that bad it just takes a verryverryverry long time. Considering RAID6, the risk of two other disks crashing during rebuild is still very small.
They are also configured with a hot spare, so even if a disk failure happens on Friday just after work, the rebuild would already be a few % done on Monday.
We have 3 of these units, so in case of a major fault the other two can take over backup jobs temporary. They are scaled for that.
Further we have a QNAP where we do full backups every weekend to. So it is possible to restore at least 7 days old backups even if one of these big units has a disastrous failure. And off cause offsite full restore points.
There is no universal-correct way to do this. It all comes down to RTO and RPOs, we find ours acceptable.
I would not consider JBOD on a 36 disk system, probably not on a 12 drive either… unless they only were used for "temp-files" or if every restore point is loaded of to external site/system (Veeam Backup Copy job).
But having nine 12-drive units would make the solution more robust,
no doubt, and to some extent more flexible. But in the process, more expensive, more rack space demanding (24u VS 12u), and more power hungry
With power comes greed… (that was a joke).
But with added power usage comes:
- The need for bigger/more UPS(maybe need for another UPS (add another 2U)
- The need for more cooling in the environment / serverroom
- A bigger power bill, obvisually
This actually sums up a bit of the reasons for our design… got a bit carried away here. Feel free to moderate the post
