I honestly don't know the terms of the guarantee at this time, but here's a few observations on this topic of efficiencies and guarantees:
1) Always read the remedies for the guarantees. They seem mostly the same to me across the vendors.
2) There's a reason for that - the efficiency rates are more or less the same for any of the various products on the market.
I've noted a few competitors who tend to cite 4:1, 5:1, or 6:1 without any qualification. On occasion, I've heard of one of them having to send lots of extra shelves of disks to make up for the shortfall, but most of the time the answer is "you had a nonstandard configuration" which is a different way of saying "too bad".
Most customers I know do see about 4:1 efficiencies when they properly implement an ONTAP 9 system, but obviously there will be variations. VDI is usually pretty easy because the VMDK's deduplicate extremely well. I've seen databases that were mostly empty and compressed and compacted 80:1. If someone is in the habit of storing loads of zeros in their databases, we'd blow that 4:1 out of the water, but that's a fringe case. It's due to compaction. All those 8K blocks are composed of a small header and trailer sandwiching some zeros. The zeros compress mostly out of existence and compaction will then store the residual header/trailer data into a tiny space. Fringe case, but not out of the question. On the flipside, I ran into a customer who was getting zero compression because their DBA's had enabled encryption across the board without telling the storage team. They were getting no savings at all. Still, 4:1 is about the typical level in my experience with ONTAP.
There's also more than just compression and efficiency. I know one customer who took a 60TB database and cloned it 40 times. That's 40:1 right there without compression or deduplication. You could do the same thing on some competing storage arrays and the clone savings would be done via deduplication, whereas we do it via direct cloning of a snapshot. It's quicker, but it's not classified as "efficiency" because it's not done via deduplication or cloning. It sometimes isn't getting the deserved credit as an efficiency option.
It's also worth mentioning the big picture. For one, the cost of SSD's keeps dropping, which erodes the value of efficiency. The cost savings are less and less all the time. Maybe some product out there does have 4:1 efficiency on a certain data set while ONTAP only had 3:1, but how much money does that really save, and what are the consequences? There are more features and needs beyond space savings. For example, some products use larger compression block sizes and get better efficiency. You could even force this with ONTAP via secondary compression which uses a larger block size and therefore delivers better efficiency levels. Unfortunately, with data sets like VDI and databases that involve small block overwrites you will see a latency hit. So, better efficiency with worse performance.
From: toasters-bounces@teaparty.net [mailto:toasters-bounces@teaparty.net] On Behalf Of jordan slingerland Sent: Thursday, September 22, 2016 1:33 PM To: toasters@teaparty.net Subject: AFF and 4:1 guaranteed efficiency
Sales guys are promising me 4:1 dedup ratios on an AFF with ontap9. They say they grantee it. I have specifically asked what stipulation. In a VDI environment with linked clones, etc. Sales guy tells me none and even specifically says they can dedup compressed video or audio (mp3) 4:1. I have A LOT of trouble believing that. So, 4:1 dedup guaranteed or what? Any comments welcome. --Jordan