Internal M2 SSD or PCIe SSD for caching

[blomquist]

Hello QNAP experts!
I have a rather luxurious "problem": I'm running a TS-473, 32GB RAM with two M.2 SATA SSDs in RAID 1 (2x 1TB Samsung 860 EVO) in the internal M.2 SSD SATA slots which are set up for R/W cache acceleration. The HDDs are four 8TB Seagate IronWolf ST8000VN004 in RAID 10. I have one storage pool with the system volume (thin volume) on the cache accelerated HDDs and another volume (thick) for virtual machines (also cache accelerated).

Now yesterday I ordered the QM2-4P-384 PCIe extension along with four 1TB Samsung 970 EVO Plus. I would like to get as much speed out of the system as possible and my question is how to configure the system. Should I use the four PCIe SSDs in the extension card in RAID 10 as cache acceleration for the HDDs and configure the two onboard SATA SSDs as RAID 1 system volume? Or vice versa, use the four PCIe SSDs in RAID 10 as system volume (is this even possible?) and use the onboard SATA SSDs as cache acceleration?

I should also mention that I'm running some docker containers in container station as well as some virtual machines in virtualization station. These should also benefit from the SSDs as much as possible.

Final question: how do I move the system from the HDDs to the SSDs without data loss? i have encrypted cloud backup with HBS 3 but i would prefer not to go this route.

Thanks a lot in advance for help, opinions, criticism.

Blomquist

[dolbyman]

I would scrap the cache and go for dedicated pools/volumes on the SSDs.
Cache has been proven to be counterproductive in most cases (at least the FB flashcache implementation that QNAP uses)
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