I have some "old" servers here, using Asus P9D-MH/SAS/10G-DUAL
This board comes with a SAS 6Gbps controller, an LSI SAS2308 which seems to be cacheless and an Intel Sata Chipset Intel C224 Sata3.
There was ESXi on this before and the performance were completely broken by that SAS controller since ESXi doesn't compensate for the lack of cache (it wants good stuff, as we all).
I'm now planning to install barebone linux on those servers and do some Linux MD Raid on those (since cacheless HW RAID is meh). For this purpose I'd rather use the SATA 3 ports on the motherboard.
Here comes the catch: I have 5 SSDs and 1 HDD (6 medias total), 4 SSDs planned in RAID 1 ( 2by2), the last SSD and the HDD as standalone drives (I don't plan to do HW RAID on those last 2 disks). This motherboard has only 4 SATA 3 ports, the last 2 of them are Sata 2's
Here's my question:
If I plug those 2 drives in the Cacheless SAS Controller in JBOD mode, would the performance be worse than being plugged into the Sata2 ports?
Subquestion: Does cache matters if I just use the controller as JBOD?
Subquestion2: Linux MD Raid > Cacheless HW RAID ?
Than you for your attention.