Today VMware announced on it’s blog that the RAID 1o requirements will be dropped, and that VMware will be supporting RAID 5 and RAID 6 as well.
So, this means that you will be able to use more of your local storage!
Before, with RAID 10 and the VSA mirroring the 2 ESXi server’s local storage, it meant that you could only use 25% of your actual storage.
See my previous posts on the vSphere 5 VSA – Virtual San Appliance:
Now, You can see a little bit of difference in storage – let’s say we have 6 – 500GB drives (3 TB total space) each in our 2 ESXi servers. (let’s ignore formating for size and just use nice round numbers.)
Here’s the differences:
Raid 10: 3 TB total space (1.5 TB per ESXi server). With RAID1 between VSA’s, you are left with 1.5TB usable.
RAID 6: 4 TB total space (2 TB per ESXi server). With RAID1 between VSA’s, you are left with 2TB usable.
RAID 5: 5 TB total space (2.5 TB per ESXi server). With RAID1 between VSA’s, you are left with 2.5TB usable.
So, assuming disk performance isn’t an issue – you have the chance to use up to 40% of your total storage instead of 25%. In this scenario, we gained an additional 1 TB of storage space.
BTW – Highly recommend going 100% write cache on your controller if you are going to use RAID5 or 6.