A Closer Look at ZFS, Vdevs and Performance


When looking at the mails and comments I get about my ZFS optimization
and my RAID-Greed posts, the same type of questions tend to pop up over and over again. Here's an example from a reader email:

"I was reading about ZFS on your blog and you mention that if I do a 6 drive array for example, and a single RAID-Z the speed of the slowest drive is the maximum I will be able to achieve, now I thought that ZFS would be better in terms of speed. Please let me know if there is a newer ZFS version that improved this or if it does not apply anymore."

This is just an example, but the basic theme is the same for much for the reactions I see: Many people think that RAID-Z will give them always good performance and are surprised that it doesn't, thinking it's a software, an OpenSolaris or a ZFS issue.

In reality, it's just pure logic and physics, and to understand that we should look a little closer at what vdevs are in ZFS and how they work.

Home Server: RAID-GREED and Why Mirroring is Still Best

Disks in a circle. How cute.

After moving my blog to its new home and getting my hands dirty with Drupal, it's time to continue my series of blog articles about setting up a home server. Remember? We talked about home server requirements, then I presented to you my small and energy-efficient, still ECC-protected and powerful AMD-based home server. Now it's time to explore some different ZFS disk pool RAID strategies.