Hi, afaik cache does not have to do anything with journals.
So your OSD's need journals, and for performance, you will take SSD's. The Cache should be something faster than your OSD's. Usually SSD or NVMe. The Cache is an extra Space in front of your OSD's which is supposed to speed up things because the cache operate faster than the OSD's and the cache will flush its content to the slower OSD's. So, the cache is independent from the OSD's. And this way, from their journals. And, the cache >must< be on faster drives than the OSD's, otherwise you wont see any performance increase. -- Mit freundlichen Gruessen / Best regards Oliver Dzombic IP-Interactive mailto:i...@ip-interactive.de Anschrift: IP Interactive UG ( haftungsbeschraenkt ) Zum Sonnenberg 1-3 63571 Gelnhausen HRB 93402 beim Amtsgericht Hanau Geschäftsführung: Oliver Dzombic Steuer Nr.: 35 236 3622 1 UST ID: DE274086107 Am 21.04.2016 um 13:27 schrieb min fang: > Hi, my ceph cluster has two pools, ssd cache tier pool and SATA backend > pool. For this configuration, do I need use SSD as journal device? I do > not know whether cache tier take the journal role? thanks > > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
