Hi Boris, not sure I understand why do you think it needs correction. IMO _use_rotational_settings() function does what you're suggesting plus it has some additional logic to be able to enforce specific device type. The latter is intended primarily for testing/debugging and enabled via 'bluestore_debug_enforce_settings' configuration setting. Thanks, Igot On 2/4/2020 8:29 PM, Boris Epstein wrote:

Hi Igor,

Thanks!

I think the code needs to be corrected - the choice criteria for which setting to use when

cct->_conf->bluestore_cache_size == 0

should be as follows:

1) See what kind of storage you have.

2) Select type-appropriate storage.

Is this code public-editable? I'll be happy to correct that.

Regards,

Boris.

On Tue, Feb 4, 2020 at 12:10 PM Igor Fedotov <ifedotov@suse.de <mailto:ifedotov@suse.de>> wrote:

Hi Boris,

general settings (unless they are set to zero) override disk-specific settings .

I.e. bluestore_cache_size overrides both bluestore_cache_size_hdd and bluestore_cache_size_ssd.

Here is the code snippet in case you know C++

   if (cct->_conf->bluestore_cache_size) {      cache_size = cct->_conf->bluestore_cache_size;    } else {      // choose global cache size based on backend type      if (_use_rotational_settings()) {        cache_size = cct->_conf->bluestore_cache_size_hdd;      } else {        cache_size = cct->_conf->bluestore_cache_size_ssd;      }    }

Thanks,

Igor

On 2/4/2020 2:14 PM, Boris Epstein wrote: > Hello list, > > As stated in this document: > > https://docs.ceph.com/docs/master/rados/configuration/bluestore-config-ref/ > > there are multiple parameters defining cache limits for BlueStore. You have > bluestore_cache_size (presumably controlling the cache size), > bluestore_cache_size_hdd (presumably doing the same for HDD storage only) > and bluestore_cache_size_ssd (presumably being the equivalent for SSD). My > question is, does bluestore_cache_size override the disk-specific > parameters, or do I need to set the disk-specific (or, rather, storage type > specific ones separately if I want to keep them to a certain value. > > Thanks in advance. > > Boris. > _______________________________________________ > ceph-users mailing list -- ceph-users@ceph.io <mailto:ceph-users@ceph.io> > To unsubscribe send an email to ceph-users-leave@ceph.io <mailto:ceph-users-leave@ceph.io>