topic Advantage of 1.8TB SAS shelves compared to 15.3TB SSD shelf? in ONTAP Hardware

Advantage of 1.8TB SAS shelves compared to 15.3TB SSD shelf?

Maurice-FreeOnes — Wed, 04 Jun 2025 09:44:22 GMT

I was wondering is there an ADVANTAGE of having 4 shelves full with 1.8 TB SAS disks compared to 1 shelves with 15.3 TB SSD disks?

I can imagine about the advantages of the 15.3TB SSD shelf, as less power costs, less broken disks, more space left in the cabinet. And I assume faster data throughput?

So I am wondering are there also disadvantages other than investing in new disks again?

Regards, Maurice

Re: Advantage of 1.8TB SAS shelves compared to 15.3TB SSD shelf?

chamfer — Tue, 03 Oct 2023 22:10:17 GMT

One advantage would be that with more than one shelf you could have shelf redundancy through the use of mirrored aggregates, but this is an edge use case. https://docs.netapp.com/us-en/ontap/disks-aggregates/mirrored-unmirrored-aggregates-concept.html#how-mirrored-local-tiers-aggregates-work

There will be an orders of magnitude performance increase when replacing 96x 1.8TB SAS HDD with 24x 15.3TB SSD. IOPS for example for a HDD is around 100-150 per drive, but a SSD has > 10,000 IOPS per drive. Throughput for a HDD is around 100-150MBps, but a SSD would be around 500MBps.

Talk to your NetApp rep and they should be able to give you a performance comparison between your current and proposed configurations.

Re: Advantage of 1.8TB SAS shelves compared to 15.3TB SSD shelf?

SpindleNinja — Mon, 09 Oct 2023 17:08:13 GMT

Outside of the edge case of mirrored aggrs on the same system- not really IMHO.

You'd have more capacity with the 15s - (114TiB vs 264TiB)
Even with all 96 spindles in a single aggr you wouldn't come close to the throughput of the SSDs.

I'm curious as to why you're asking this question.

Re: Advantage of 1.8TB SAS shelves compared to 15.3TB SSD shelf?

Maurice-FreeOnes — Mon, 09 Oct 2023 20:17:50 GMT

I was aksing this question mostly because in the past somebody told me that big SSD's can slow things down. However from the answers this doesn't seem to be the case.

Re: Advantage of 1.8TB SAS shelves compared to 15.3TB SSD shelf?

SpindleNinja — Tue, 10 Oct 2023 12:44:24 GMT

Larger drives have slower rebuild times.

Re: Advantage of 1.8TB SAS shelves compared to 15.3TB SSD shelf?

MaGr — Fri, 27 Oct 2023 11:46:07 GMT

Hey,

If you have experienced SSD speed you never want that spinning rust again 🙂

Your disk backend will be never again the bottleneck.

With a AFF you have more efficiency possibilities to save space.

Re: Advantage of 1.8TB SAS shelves compared to 15.3TB SSD shelf?

MaGr — Fri, 27 Oct 2023 11:47:48 GMT

the mirrored aggregates are a Metrocluster feature.

Re: Advantage of 1.8TB SAS shelves compared to 15.3TB SSD shelf?

MaGr — Fri, 27 Oct 2023 11:49:12 GMT

Yes, in case of NL-SAS.

That's why they invented Raid-TEC. Takes just some days to rebuild 10TB a disk.