XigmaNAS

The simplest answer would probably be two identical RAIDZ3 machines, but I would like to avoid having to backup my data twice.

I have therefore thought of a setup that I believe can survive the failure of any one component, but have no experience and would like your opinions.


The Zpool consists of RAIDZ3 vdevs consisting of 5 drives each, one disk from each pool is connected to an onboard SATA port and the rest to 2-port SATA controllers.
The system is powered by 3 power supplies, each on their own UPS: One powers the motherboard plus one disk in each vdev, and the other two are connected to two drives in each vdev.


That way any power supply or UPS can fry its components, or one SATA controller can die, but the data can still be accessed.


But perhaps there was something I missed? Or maybe I've over thought the whole thing?




Also, is my understanding correct in that if the motherboard happens to fail when using the embedded version of NAS4FREE, it can be replaced with a completely different one without NAS4FREE caring?

I would like to avoid having to backup my data twice.

That is the wrong starting poit. If you care about your data, you NEED a backup.
Non backupped data can be considered as lost data from the beginning.
Other to hardware failures a backup preserves you from file deletions by mistake and there are other impacts like hardware failures which can lead to data loss, like fire, water damage etc.

he system is powered by 3 power supplies, each on their own UPS: One powers the motherboard plus one disk in each vdev, and the other two are connected to two drives in each vdev.

How do you power the other two up, when only one is connected to the mainboard?
You can also consider buying a server case with redundant PSUs.

But perhaps there was something I missed?

Buy your disks from different batches.

Also, is my understanding correct in that if the motherboard happens to fail when using the embedded version of NAS4FREE, it can be replaced with a completely different one without NAS4FREE caring?

Yes when you saved the coonfiguration, you can restore it easily on a new system.

crowi wrote:

he system is powered by 3 power supplies, each on their own UPS: One powers the motherboard plus one disk in each vdev, and the other two are connected to two drives in each vdev.

How do you power the other two up, when only one is connected to the mainboard?
You can also consider buying a server case with redundant PSUs.

With a pair of these: http://www.frozencpu.com/products/5637/ ... Cable.html

I considered a redundant power supply, but the ones I saw all appear to have loud cooling fans, and I want the system to be as quiet as possible.

i agree with crowi. all the data in one case is not a backup.
what if you accidentally destroy your zpools?
or issue the command rm -rf /
etc...

you don't need the same machine for the backup and the backup does not have to be onto zfs.
the cheapest option is to get a hp n54l as your backup machine. (depending on where you life there a great deals atm)

b0ssman wrote:i agree with crowi. all the data in one case is not a backup.
what if you accidentally destroy your zpools?
or issue the command rm -rf /
etc...

you don't need the same machine for the backup and the backup does not have to be onto zfs.
the cheapest option is to get a hp n54l as your backup machine. (depending on where you life there a great deals atm)

This will be a dedicated backup machine, not the same box holding the data to be backed up.

I want the backups to be in a ZFS file system on an error-correcting motherboard to avoid corruptions, but I also want my vdevs and zpools to survive a hardware failure.



I am willing to backup my data to two separate N4F systems each week, but I'm looking for an alternative to having to run the operation twice.

I can see two easy ways of solving your situation.

First using HAST (TWO nas MACHINES), you will do the backup only once, but there will be two identical copies.

The second, create a scheduled rsync to create secundary copies of the backup on secondary NAS (you can even have diferent politics on the replication with a delay in the deletions, etc).

Or with only one NAS you can use scheduled snapshots.