Hi Norman

On Mon, Mar 1, 2021 at 4:38 AM Norman.Kern <norman.k...@gmx.com> wrote:

> Hi, guys
>
> I am testing ceph on bcache devices,  I found the performance is not good
> as expected. Does anyone have any best practices for it?  Thanks.
>

I've used bcache quite a bit with Ceph with the following configuration
options tweaked

a) use writeback mode rather than writethrough (which is the default)

This ensures that the cache device is actually used for write caching

b) turn off the sequential cutoff

sequential_cutoff = 0

This means that sequential writes will also always go to the cache device
rather than the backing device

c) disable the congestion read and write thresholds

congested_read_threshold_us = congested_write_threshold_us = 0

The following repository:

https://git.launchpad.net/charm-bcache-tuning/tree/src/files

has a python script and systemd configuration todo b) and c) automatically
on all bcache devices on boot; a) we let the provisioning system take care
of.

HTH


> _______________________________________________
> ceph-users mailing list -- ceph-users@ceph.io
> To unsubscribe send an email to ceph-users-le...@ceph.io
>
_______________________________________________
ceph-users mailing list -- ceph-users@ceph.io
To unsubscribe send an email to ceph-users-le...@ceph.io

Reply via email to