We have 3 nodes with 2x960GB SSD and 4x4TB HDD.
We need to expand storage (and storage only as it is going to be used to store cold data - we do not need additional processing power or RAM)
Question 1: We simply added two 12TB HDDs to each node. Now each node has 2x960GB SSD, 4x4TB HDDs, 2x12TB HDDs. Everything is working fine, but we were told that this is not recommended. What is the problem with this configuration
Question 2: Assuming the configuration in Q1 is not recommended and we want to end up with each node having one type of HDDs. We were told that we can upgrade the existing 4TB HDDs with 12TB drives. What the right procedure would be:
a) Mark one 4TB drive for removal, remove it, insert 12TB drive in place of removed 4TB drive. Repeat 4 times for a node. Resulting configuration - 6x12TB HDDs per node
b) Add two more 12TB drives first, then mark for removal and remove four 4TB drives (one by one). Resulting configuration - 4x12TB HDDs per node (preferred configuration by us)