A couple of weeks ago I wrote a blog post about NetApp Deduplication. The post gave a non-technical explanation of Deduplication. In that post I mentioned that we would have additional discussions around NetApp’s advertised storage efficiencies. In this post, we’ll start off the series with a discussion on flexible volumes. Flexible volumes (FlexVols) were introduced with Data ONTAP 7 and are a foundational requirement for NetApp storage efficiencies.
Flexible volumes live inside of an aggregate. An aggregate has the same physical characteristics as a traditional volume, but one major difference is that multiple flexible volumes can exist within one aggregate. Aggregates and traditional volumes reside on top of raid-groups and these raid-groups are made of physical disk collections residing on the storage disk shelves.
Raid-groups are the first line of defense in data protection. NetApp offers two types of raid level protection, RAID 4 and RAID-DP. RAID 4 protects against a single disk failure, while RAID-DP protects against double-disk failure.
Once an aggregate is created, an administrator can create multiple flexible volumes within that aggregate and these volumes can be grown or shrunk on the fly. The advantage of this is that a large amount of free space does not have to be pre-allocated to end-users as the administrator can simply grow a volume as needed or take away pre-allocated space that is not being used without impacting end-user access to the data within that volume. Another benefit of Flexible volumes is improved performance since all flexible volumes within an aggregate share disk spindles.
I thought it was important to start off the series with a quick introduction to flexible volumes because NetApp storage efficiencies are not possible without flexible volumes. In our next discussion we will continue our storage efficiency series with an introduction to NetApp thin provisioning.