FreeNAS storage upgrade article

[liteswap]

Almost ten years into my FreeNAS experience, I recently had to upgrade my (old and getting older) storage. So I wrote up the experience, which you may (or may not) find useful, helpful, even (in parts) entertaining.

Project: Build Your Own NAS (Part 1) - Tested Technology

A centralised server in your home or office—usually called a NAS (Network Attached Storage) can be a great way to make sure that all your information and entertainment material is secure and available wherever and whenever you need it. Veteran IT journalist Manek Dubash tells us how you can roll...

www.testedtechnology.co.uk

 

[Spearfoot]

Almost ten years into my FreeNAS experience, I recently had to upgrade my (old and getting older) storage. So I wrote upo the experience, which you may (or may not) find useful, helpful, even (in parts) entertaining.

Project: Build Your Own NAS (Part 1) - Tested Technology

A centralised server in your home or office—usually called a NAS (Network Attached Storage) can be a great way to make sure that all your information and entertainment material is secure and available wherever and whenever you need it. Veteran IT journalist Manek Dubash tells us how you can roll...

www.testedtechnology.co.uk

Well-written and informative article, which I enjoyed reading. I appreciate that you addressed the issues inherent with RAIDZ1 when you selected it for your design.

I have one criticism, which I humbly offer: your description of RAIDZ1 isn't accurate:

A RAID-Z1 array, like RAID5, devotes one of its disks to parity. If a disk fails, the remaining disks can continue serving valid data while a replacement disk is installed. If it’s the parity disk that has failed, the system will just have to assume the data on the other drives is good as it continues to offer up its contents to the network.

If one of the data drives has failed, the parity disk will be able to compute, on the fly, what the missing data should have been and be able to serve that up as required.

There are no dedicated data or parity disks per se in a RAIDZ pool; these are distributed across all disks in the vdev.

See, for example, the "Overview of ZFS Pools in FreeNAS" on the iXsystems blog:

RAIDZ1 requires at least three disks per vdev and consumes one drive’s worth of capacity for parity protection distributed across all the drives.

 

[liteswap]

Thanks for the kind comments. You're right of course about RAID-Z1. I should have said "equivalent of one disk for parity". I'll get it changed.