Vlad, thanks for the information. I will review it shortly. I do have SSDs and SAS (not sata) disks in the same box. But I guess there shouldn't be much difference between SAS and SATA. At the moment I am running firefly. I've seen some comments that the master branch has a great deal of improvements introduce to accommodate high IO of the SSDs. Does that apply to the improvements of the cache tier as well? Cheers Andrei ----- Original Message ----- From: "Vladislav Gorbunov" <vadikgo@xxxxxxxxx> To: "Andrei Mikhailovsky" <andrei at arhont.com> Cc: ceph-users at lists.ceph.com Sent: Thursday, 4 September, 2014 1:52:05 AM Subject: Re: Cache pool - step by step guide You mix sata and ssd disks within the same server? Read this: http://www.sebastien-han.fr/blog/2014/08/25/ceph-mix-sata-and-ssd-within-the-same-box/ When you have different pools for sata and ssd configure cache-pool: ceph osd tier add satapool ssdpool ceph osd tier cache-mode ssdpool writeback ceph osd pool set ssdpool hit_set_type bloom ceph osd pool set ssdpool hit_set_count 1 In this example 80-85% of the cache pool is equal to 280GB ceph osd pool set ssdpool target_max_bytes $((280*1024*1024*1024)) ceph osd tier set-overlay satapool ssdpool ceph osd pool set ssdpool hit_set_period 300 ceph osd pool set ssdpool cache_min_flush_age 300 # 10 minutes ceph osd pool set ssdpool cache_min_evict_age 1800 # 30 minutes ceph osd pool set ssdpool cache_target_dirty_ratio .4 ceph osd pool set ssdpool cache_target_full_ratio .8 Remember, that the current stable ceph 0.80.5 cache pool osds crashing when data is evicting to underlying storage pool. See http://tracker.ceph.com/issues/8982 2014-09-04 10:55 GMT+12:00 Andrei Mikhailovsky < andrei at arhont.com > : Hello guys, I was wondering if someone could point me in the right direction of a step by step guide on setting up a cache pool. I've seen the http://ceph.com/docs/firefly/dev/cache-pool/ . However, it has no mentioning of the first steps that one need to take. For instance, I've got my ssd disks plugged into the osd servers. What do I do next? How do i create the initial pool made just of these ssds and promote it to the cache pool status. How do i choose the right cache pool sizing, number of PGs, etc. Thanks Andrei _______________________________________________ ceph-users mailing list ceph-users at lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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