[ceph-users] Re: Do not use SSDs with (small) SLC cache

Michael Wodniok (wodniok) writes:

Hi all,

digging around debugging, why our (small: 10 Hosts/~60 OSDs) cluster is so slow even while recovering I found out one of our key issues are some SSDs with SLC cache (in our case Samsung SSD 870 EVO) - which we just recycled from other use cases in the hope to speed up our mainly hdd based cluster. We know it's a little bit random which objects get accelerated when not used as cache.

Somewhat off-topic, but... may I recommend *not* using the 870s ? There is an issue with 870s failing around 14-17 TB written if they're not running the latest firmware... I recently pulled 25 of them out of our storage because of this. https://twitter.com/regnauld/status/1502185863052152833 Cheers, Phil