Today, we are going to take a look at RAID Groups versus storage pools and give some tips about which would be more beneficial for your organization.
What is a Storage Pool?
A storage pool is essentially capacity that is aggregated from various physical storage resources into a shared storage environment. Storage pools can give you a multitude of different things that can help make storage management more simplified. When you have a storage pool, you no longer have to think about how many IOPS you will need to squeeze out of a certain amount of drives. Storage pools allows you to put multiple different types of drives into one container. So, you can have a storage pool that has a tier of SATA drives, a tier of SAS drives or Fibre Channel drives, and a tier of EFD.
What do you get from this?
Benefits of Storage Pools
• Higher Spindle Count: Storage Pools give you a higher spindle count than you can get out of a traditional RAID group.
• Flexibility: A traditional RAID group will max out at a specific number of disks versus in a storage pool you can have hundreds of disks in your pool.
• Tiering: You can have various types of disks in one storage pool; so if you have an environment that has hot blocks versus cold blocks, the array has software in place to identify which blocks are being accessed frequently. It will then move them into a faster tier such as the Fibre Channel or EFD tier. The blocks that are not being accessed as frequently will be moved down to SATA.
• Ease of Management: With a traditional RAID Group, expanding a LUN requires a bit more work. Let’s say you have a 100 gig LUN and you want to move to a 150 gig LUN, you create a new 50 gig LUN and you consolidate them together to create a larger LUN. A storage pool only requires you to right click on the LUN and say, “expand” and the array will do all the math behind the scenes and present to the host a larger LUN.
Then End of the RAID Group?
While there are definitely benefits to storage pools, this does not mean that the days of the RAID groups are over. Some environments will need a guarantee of a specific numbers of IOPS. The way to do this is via a RAID Group because you will want to isolate a subset of spindles to an environment so you can guarantee that this environment will get a peak number of IOPS at any given point throughout the day.
Essentially, when you really need to narrow the type of performance that an environment needs, the RAID group is still the best way to go.