RaidZ1 question

[Xenner]

Guys,

Putting the finishing touches on my ESXi/ZFS box.

I have it up and running with 3x2tb Seagate drives (got them on Craigslist for $70 each still in warranty, can't beat that price.) Problem is for me to get a 4th, it would be ridiculously expensive.

I do have a 1.5TB Samsung drive sitting around here..would it be wise for me to just do a 4 drive raidz1 vs a 3 drive...

right now with the 3x2tb drives I have 3.2TB useable space after the 90% cap. If I went with the 4 drive setup (only using 1.5tb on each 2tb drive) I would be at 4.05TB, and then if I was to find another seagate drive, I could pull the 1.5, rebuild the array with all 2TB drives and expand it out to 5.4TB, is this correct?

Thanks,

 

[_Gea]

correct.

But if you do not need max capacity, consider Raid-10
2 + 2 TB
1,5 + 2 TB

gives you 3,5 TB but with much better I/O performance
Next disk should be a 2 TB hotfix for better reliabilty
You can increase capacity and performance easily by adding more 2 TB mirrors

 

[Xenner]

So that would be two different vdevs? I would just add them to the same pool and it would act exactly the same??

 

[_Gea]

So that would be two different vdevs? I would just add them to the same pool and it would act exactly the same??

ZFS stores data on a pool. A pool consists of one or more vdevs.
Each new vdev adds not only capacity to a pool but also performance.
The more vdevs you have the better.

A pool from a single Raid-Z vdev with a lot of disks is only good if you
mainly need max capacity. I/O performance is as good (bad) as a single disk.