Thx mike, your help was invaluable believe me
Now
Congrats on your upgrade and glad that things seem to be working out to your liking. I'm curious though. By putting your nearline disks in a seperate pool, they are not part of the tiering strategy on Pool A. This means that cold data can never migrate all the way down to the nearline disks. Certainly OK if that is your intention.
Yes i did that after big thought because i have the HP 81Q cards at this momment and with this in mind my 4 hosts need to be fast in PoolA where the VM system disks relies and also the SSD disks for performance.
Also i didnt want to raise the Usable space of the PoolA because then the 2 SSDs that give me 400GB are not enouph according to HP, to get good performance from tiering. You need to have 10% of usable space at least( i know its not holy grail but i respected it), so if i had put the 4 x MDLs in PoolA suddenly from 2.8TB usable space i would had gone to 8.8TB usable space all in Pool A with under 5% of SSDs for performance tiering. I also considered the scenario to brake the 4 MDL's with 2 in POOLA and 2 in POOLB but with that way i loose disk speed since the more the disks together the faster througput you get.
Also the MDL disks contain only SMB data (and backup space that is workign in nights) which in my case are accessed by Windows Terminals (virtual or Physical) that dont need extra speed for this. From test as we speak i get 100MB/sec or more speed from the MDL's which is totally acceptable (with the P2000G3 i was getting under 60MB/sec). If i buy 2-3 more SSD's to make the POOL A bigger in performance tiering then i will reformat everything and redo all the work but i really dont think is needed.
I include a screenshot of the speeds that i get from HD Tune.
The left image is from a System disk of a server that relies on the POOL A and the 2nd is from the SMB Server that uses the MDL's in POOL B (i didnt had any other way to measure speed.. if there is i am willing to do tests for sure)
You also said that all your hosts are connected to just the first controller (assuming controller A). This would typically mean that your hosts wouldn't have access to volumes on Pool B (if using ALUA) since Pool B should be owned by controller A and you say your hosts don't have access to controller B. So, If this is truly the case then you are probably sending IO (to the controller B) volumes via controller A. This is considered a non-optimzed path and will increase the backend IO between the controllers and potentially decrease performance.
Yes this is the case. All my hosts are in 1st controller and to access the 2nd Pool controller A gets what it needs from controller B. I know this is not optimal but works and the speed penalty is not big in my scenario. For a moment i thought creating a Linear group of the MDL's and assign it to Controller A but then i decided to use the 2nd controller even like this, because we must not forget that the 2nd controller has extreme fast cache and with that way is usable (i hope i am not wrong).
Generally i plan to buy more disks and i am thinking
A. 2 x 400GB ssd's and i will use all 4 and in the end i will get 800GB performance tier space where i have a raid question atm :-). Question is when i buy the 2 SSD's i just create another raid 1 in pool A or i delete the 1st SSD group that i have atm and with the 4 SSD's together i create a new Raid10 (or raid 5 maybe)? is there any performance gain doing this?
B. 8x600GB SAS to add them in PoolA. Question here is if i really need to buy 15K disks since my 1st 8x600GB disks are 15k. I know HP says is supported but its better not to mix different speed disks in same Tiering. Maybe i can buy 8x600 10K disks and assign them as Archive tier in POOL A.
Thx for your notes and help really... i will reconsider some things for sure.
Kind Regards
Chris