A slightly different comparison of SSD and HDD Storage

By | 17. July 2020

Hello, everyone,
today I would like to give you an overview of the advantages of All-Flash systems compared to systems with spinning media.

I can hear you screaming already:

“Oh, no. Not another blog about the advantages of All-Flash systems! Now DerSchmitz is going crazy!”

Of course, you know that All-Flash systems are faster than systems with rotating spindles. I (hopefully) don’t need to tell you that here.

What I want to tell you about are some other interesting facts, which are often ignored in the HDD vs. SSD discussion.

In order to avoid Competitor Bashing, I compare NetApp with NetApp here. I leave the transfer to other manufacturers to the inclined and attentive reader himself.

So what are the advantages of All Flash compared to pure HDD systems?

The counterparties:

  • a NetApp FAS 3220HA with 48x 1TB BSAS and 72 x 2TB BSAS HDDs (approximate capacity 124 TB)
  • a NetApp AFF A220 with 24x 3.84TB SSD

Round 1: Rack units

The AFF A220 requires 2 rack units, the FAS requires 26 rack units. Clear winner the All-Flash machine. Height units in the data center also cost money.

Round 2: Capacity

It looks weird, but it’s true. The AFF manages to accommodate 165 TB in 2 height units. The FAS on the other hand “only” manages
124 TB at 26 height units.

Those of you who have counted further up in the number of discs and disc sizes will now say I am telling lies. “No way.” Yes, it can. Because the efficiency mechanisms of NetApp All Flash systems give us an efficiency ratio of 3:1, which is also guaranteed by NetApp. (Except for encrypted data and already compressed data like pictures). If other manufacturers promise you better efficiencies, I would at least recommend reading the small print 😉

Round 3: SnapShots

Since we compare two NetApp systems here and this is also a comparison between “Then & Today”, the new AFF A220 can hold significantly more SnapShots per volume than the “old” FAS 3220. The AFF can create 1023 SnapShots per volume, the old FAS only 255.

Round 4: Power consumption

Now things are getting interesting! If the FAS 3220HA consumes 25,736 kWh/year, the AFF A220 consumes only 3296 kWh/year.

Why is that so interesting? Well… electricity costs money! And no the electricity doesn’t just come out of the socket 😉
Here is a small sample calculation:

Over five years I can save almost 32.000 EURO here!

Round 5: Indirect electricity costs

During the operation of electronic devices waste heat is generated, which must be compensated by air conditioning, otherwise the devices will stop operating due to overheating. The waste heat generated by electronic equipment is stated by the manufacturers in BTU/h (British Thermal Units). The previously used FAS 3220 generates 10016 BTU/h waste heat, whereas the new AFF A220 generates only 1284 BTU/h waste heat.

Why are the BUT/h interesting? For cooling I also need energy, i.e. electricity. This electricity also costs money. No, also here the electricity does not simply come from the socket 😉
Another example calculation:

If you want to calculate, here is the formula:

So you see, with All Flash systems it is not always just about speed. The increased performance and low latency are often just the icing on the cake.

Conclusion All Flash vs. Hdds:

Even for customers who do not have high performance and low latency requirements, an All Flash system will be economically viable.

  • Fewer height units in the datacenter
  • More space and fewer hardware thanks to efficiency technology
  • Lower power consumption and therefore lower operating costs

In short: More net of gross

And yes… of course there is still a right to exist for spinning media. Let’s just think about archive data or video storage.

I would like to thank the customer, who may recognize himself here from a past project.

Best regards


DISCLAIMER: This post represents my personal observations and is not officially by NetApp or other authorized. Subject to misinterpretation or misunderstanding.

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