How to allocate SSD for OSD DB and WAL?

[Jordan.zhang]

I have two 3.84TB SSDs and eight 4TB HDDs. I want to allocate the two SSDs for OSD DB and WAL usage. However, if one SSD is associated with four HDDs, a failure of one SSD would affect all four HDDs. Is there a better approach to minimize the impact of an SSD failure on the HDDs? Can I use hardware RAID on these two SSDs and then for all OSD DB and WAL?

 

[Jordan.zhang]

Can I configure Ceph cache tiering in the PVE environment to solve the issue I mentioned above?

 

[LnxBil]

if one SSD is associated with four HDDs, a failure of one SSD would affect all four HDDs.

That is true.

Is there a better approach to minimize the impact of an SSD failure on the HDDs? Can I use hardware RAID on these two SSDs and then for all OSD DB and WAL?

Yes, theoretically you can use technologies like RAID (hardware or software) for that, yet it can introduce new problems. It is also not the recommended or supported configuration.

 

[Jordan.zhang]

Dear LnxBil,
Thanks for your replay that is very helpful information for me.