3 ms·
Maybe I'm doing something horribly wrong. My setup was: - 6x4TB HDD - 2x120GB SSD - OSD per disk - k=4,m=2 erasure coded HDD pool - 1 copy replicated (not)
by Veratyr 10y ago
Maybe I'm doing something horribly wrong. My setup was:
- 6x4TB HDD
- 2x120GB SSD
- OSD per disk
- k=4,m=2 erasure coded HDD pool
- 1 copy replicated (not) SSD pool
- SSD pool writeback cache for HDD pool
I was consistently seeing the SSD writeback cache fill up then the disks thrashed at 100% IO utilization, limiting incoming writes to ~40MB/s from memory.
- ymse 10y agoOops, didn't see this reply until now. It's no longer recommended to use a SSD cache pool, much for the reasons you describe. You will be a lot better off using bcache or similar, on top of the OSD device.