Hi Ashley,
You could move your Journal to another SSD this would remove the double write.
If I move the journal to another SSD, I will loss an available OSD, so this is likely to say improve of
x2 and then decrease of
x½ ...
this should not improve performance in any case on a full SSD disks system.
Ideally you’d want one or two PCIe NVME in the servers for the Journal.
This seems a really good Idea, but image that I have only 2 slots for PCIe and 12 SSD disks.
I image that it's will not be possible place 12 Journal on 2 PCIe NVME without loss performance..... or yes?
Or if you can hold off a bit then bluestore, which removes the double write, however is still handy to move some of the services to a seperate disk.
I hear that bluestore will remove double writing on journal (still not investigated), but I guess Luminous will be fully tested not before the end of the year.
About the today system really don't know if moving on a separate disks will have some impact considering that this is a full SSD disks system.
Even adding 2 PCIe NVME.... why should not use them as a OSD instead of journal solo?