The Myth of Effective Storage Capacity


March 14, 2016

by Gary Archer

I sometimes hear customers say that they get more for their Dollar (or Pound, Yen or Euro) with a competitor than with TrueNAS. As I’ve said in the past, this is a myth. If you ask a vendor for a quote for usable storage30TB of storage, do you get 30TB of usable storage? You will from iXsystems, but from the others you will not get it as often as you might expect. This blog post details what you get with iXsystems and how some vendors entice you with their myth of storage capacity.

Many vendors often give you a storage quote that depends on storage optimization. If you purchase from them and don’t see the storage optimization you expected, you will have no choice but to purchase additional physical storage, increasing your cost per GB. The quote you get from iXsystems always relies on usable storage capacity and separately shows you the benefits of compression and deduplication. Let me start by defining the three storage capacities and show you what you are getting from other vendors.

  • Physical/RAW storage capacity is what you get before formatting and applying RAID and before compression and deduplication. If you have 10 hard disks of 3 TB each then you have 30TB of physical storage capacity.
  • Usable storage capacity is what you have after formating, applying RAID, and accounting for hot-spare drives and other overhead. With iXsystems, if you have 10 3TB drives, in a RAID-Z2 (similar to RAID-6 since it uses two parity drives), then your space is about 21.6TB. Some competitors might state that this RAID configuration would provide 24TB of space, but they are not taking into account that drive capacity is specified in multiples of 1000, so the 3TB is about 2.7TB of usable space. At iXsystems, we include this information when determining usable capacity, so you are not blindsided into thinking you are going to get 24TB of usable space when it is really only 21.6TB.
  • Effective storage capacity is what you have after compression and deduplication. If the effect of storage optimization is 5:1 then the effective storage capacity is 5x usable capacity. The 21.6TB of usable storage above becomes 108TB of effective storage capacity. This 108TB is not reachable if you store files that are already compressed such as audio data.

checkmarkA competitor that bases their quote on effective storage capacity, in other words smaller usable storage capacity, should concern you. These vendors assume you’ll get the missing capacity from compression and deduplication. iXsystems does not give you a quote that depends on storage optimization. If you ask for a quote for 30TB of storage, we will quote 30TB of usable storage and tell you what to expect from compression and deduplication. Unlike other vendors, iXsystems never depends upon storage optimization to lower the $/GB. This myth is busted!!

Join us for a free webinar with iXsystems Co-Founder, Matt Olander, and head of sales Matt Finney to learn about the different products in the iXsystems storage family and find the storage that’s right for you.

To learn more about using TrueNAS for your storage needs see, email, or call us at 1-855-GREP-4-IX.

Gary Archer, Director of Storage Marketing

Gary brings more than 30 years of marketing and product management experience to iXsystems. In this role, he has the goal of positioning iXsystems as a leader in storage products. Before joining iXsystems, Gary served in various engineering, product management and marketing roles at EMC, IBM, and Legato Systems, He was an early member of SNIA and served two terms on its board. Gary graduated with honors from Trinity University with a dual degree in Marketing and Computer Science.

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