RAID10 of 16 disks: how to convert to RAID10 of 14 disks?

Question

RAID

There is a controller for 16 disks, it has a RAID 10 array of 16 disks of 10TB each.
Controller = Adaptec 81605ZQ
This controller supports caching through an SSD drive (maxCache SSD Caching), but, for some reason, during the initial RAID assembly, it was decided not to use this caching.
And now the task was set to include it, because it should increase performance when working with the database.
In fact, the task is to convert RAID 10 of 16 disks
into RAID 10 of 14 disks + Hotspare + SSD disk for cache
The amount of data on the RAID is monstrous - about 35 TB out of 70 are occupied, there is nowhere to pour them, and it would take it's a lot of time...
The question is - is it possible to somehow convert a RAID10 of 16 disks into a RAID10 of 14 disks without losing data in the array?

Answer 1

Such controllers seem to be able to change the array level without data loss, it is logical to assume that the number of disks will change without loss - the manual will tell you best, BUT:
- backup is required
- rebuild time .... well .... about a week, probably. .. Estimate yourself based on the raw volume and the average linear speed of the disk
- the backup support will tell you first of all
- for the time of the rebuild, the performance will decrease
PS. Usually, if there is $ for such machines, there is $ for the 2nd similar machine under the backup of the first