another thing that can help OOM cases, avoid using rbd client on same
host as OSDs. This was a general recommendation aseptically with earlier
kernels (3.x).
On 26/01/2023 23:51, Stefan Hajnoczi wrote:
On Thu, Jan 26, 2023 at 08:14:22PM +0200, Maged Mokhtar wrote:
in case of object map which the driver loads, takes 2 bits per 4 MB of image
size. 16 TB image requires 1 MB of memory.
I was trying to get a sense ofwhether to look deeper into the rbd driver in a OOM kill scenario.
If you are looking into OOM, maybe look into lowering queue_depth which you can specify when you map the image. Technically it belongs to the block layer queue rather than the rbd driver itself, If you write 4MB block size and your queue_depth is 1000, you need 4GB memory for inflight data for that single image, if you have many images it could add up.
Thanks!
Stefan
