Windows Server 2012 Essentials Storage Spaces Vs. RAID

In Windows Server 2012 Essentials as with the whole Windows 6.2 kernel family, Storage Spaces and Storage Pools re-invent the concept of Drive Extender from Windows Home Server v1. With several options for resiliency in Storage Pools, I thought I would touch on what bang you will get for your buck with each protection level and compare it to physical RAID levels.

For all the examples, I will be using 2 500GB disks unless the example requires more such as RAID 5 or 10 where I will use the minimum number required to achieve the set. If you are using 1TB, 2TB or greater sized disks, then simply multiply the figures here to work out your gains.

RAID 0 (Stripe – No Resiliency in Disks, Two Disks Required)
1TB Raw / 1TB Usable

RAID 1 (Mirror – Single Disk Resiliency, Two Disks Required)
1TB Raw / 500GB Usable

RAID 5 (Stripe with Parity – Single Disk Resiliency, Three Disks Required)
1.5TB Raw / 1TB Usable

RAID 10 (Mirror of Stripes – One Disk in Either Stripe or Both Disks in One Strip May Fail, Four Disks Required)
2TB Raw / 1TB Usable

Storage Space Simple (Equivalent to RAID 0 – No Resiliency in Disks, One Disk Required)
500GB Raw / 500GB Usable

Storage Space Two Way Mirror (Equivalent to RAID 1 – Single Disk Resiliency, Two Disks Required)
1TB Raw / 500GB Usable

Storage Space Three Way Mirror (Equivalent to RAID 1 with a 2nd Mirror – Two Disk Resiliency, Three Disks Required)
1.5TB Raw / 500GB Usable

Storage Space Parity (Equivalent to RAID 5 – One Disk Resiliency, Three Disks Required)
1.5TB Raw / 1TB Usable

The thing to be clear on Storage Pools and Storage Spaces over traditional RAID is that RAID consumes the entire disk, obscuring it to the physical operating system and limits you to the capacity of the underlying disk subsystem. This makes adding new disk to an existing RAID set and extending it’s capacity challenging unless you are using RAID 5 whereby you can simply add disk and extend capacity. Storage Pools and Storage Spaces are different in that the Pool amalgamates the capacity of the underlying disks together, then pools overlay the disks to provide the availability. This allows you to do clever things like use three disks in a single Pool to provide both a Two Way Mirror to provide protection to read/write files such as documents and a Parity to provide protection to read only workloads such as video or music files, maximising the yield from your disk investment. With RAID, so achieve these separate protection levels, you would need five disk instead of three.

I think the only challenge with Storage Pools and Storage Spaces is going to be to calculate the capacity requirements and optimising the use of the disks: In my scenario I have 6 2TB disks and trying to decide what levels to protect the different content types at and whether to split each workload type into a dedicated Storage Space or whether to Pool Spaces between workloads is interesting as I want to make sure that my content is protected as effectively as I need it, but at the same time, as a consumer, I can’t afford to blow £150-£200 on new disks all the time so I need to maximise my investments.

The core advantage of Storage Pools and Storage Spaces for me over RAID is that it does allow you to fine-grain control your disks making the most out of them, thin-provisioning (over provisioning as it actually should be called) allows me to design the disks for future expansion ahead of time and it allows me to add disks and expand pools (online) without complicated RAID array configurations, changes and scary thoughts of migrating RAID levels (if you have a controller which supports such a thing).

I’ll be doing another post in the coming days on my options for Storage Pools and Storage Spaces, and where I am leaning and why.

richardjgreen

Richard works as a Cloud Consultant for Fordway Solution where his primary focus is to help customers understand, adopt and develop with Microsoft Azure, Office 365 and System Center. Richard Green is an IT Pro with over 15 years' of experience in all things Microsoft including System Center and Office 365. He has previously worked as a System Center consultant and as an internal solutions architect across many verticals. Outside of work, he loves motorbikes and is part of the orange army, marshaling for NGRRC, British Superbikes and MotoGP. He is also an Assistant Cub Scout Leader.