ONTAP Hardware

SSD vs SAS on FAS3240 7-mode




I need to increase the SAS capacity on our FAS3240 7-mode.


The question between SSD or SAS arises. I know that the SSD is not fully "exploited" by the 7-mode. I don't want buy SSD if the performance will not be better thans SAS.


Our FAS3240 response time is good and we havn't performance issue today. 


The system has:

- 5 years old

- 350 VMs

- 40TB SAS 10K in one aggr of 48 disks

- 10TB SAS 15K in one aggr 24 disks.

- Flash cash



The question is: Do you think SSD will provide better performances than SAS in this case ?



Thanks for your advises





Hi, you should check if it's a business case for you to change to AFF. There are 3 shelves connected and you want to go for a 4th one. With the inline compression you need less capacity that before. Calculate the rack space, cooling maintenance etc. M.


Hi, thanks for your reply. Migrate to AFF is not possible. We have also SATA shelf connected to this FAS. We have to stay in 7-mode and keep SAS and SATA shelf. We don't want use inline compression because of performance and CPU usage.






run the AWA command to determine if SSD disks are required.




Thanks, I'm allready using flash cash and I don't want to add flashpool, but only SSD full aggr. I don't think AWA will help me.


I know there is a lot of steps beetween the disk and the end user application, and performance questions are alwayse difficult to answer.


From your experience, do you think SSD will add better performence on 7-mode or cluster-mode "no AFF". 

Add SSD aggr will increase CPU usage of my 3240 ?





Hi, SSD will add performance if the bottleneck is the IO related. Whats the CPU and disk load? How do the CP looks like? Does the 3240 support SSD? If your systems suffers on bore-out syndrom, SSD is just a waste of money. Whats the over-all config of this system? M.