Wed, 4 Sep 2019 11:11:14 +0200 Yoann Moulin <yoann.moulin@xxxxxxx> ==> ceph-users@xxxxxxx : > Le 04/09/2019 à 11:01, Lars Täuber a écrit : > > Wed, 4 Sep 2019 10:32:56 +0200 > > Yoann Moulin <yoann.moulin@xxxxxxx> ==> ceph-users@xxxxxxx : > >> Hello, > >> > >>> Tue, 3 Sep 2019 11:28:20 +0200 > >>> Yoann Moulin <yoann.moulin@xxxxxxx> ==> ceph-users@xxxxxxx : > >>>> Is it better to put all WAL on one SSD and all DBs on the other one? Or put WAL and DB of the first 5 OSDs on the first SSD and the 5 others on > >>>> the second one. > >>> > >>> I don't know if this has a relevant impact on the latency/speed of the ceph system but we use LVM on top of a SW RAID 1 over two SSDs for WAL & DB on this RAID1. > >> > >> What is the recommended size for wall and db in my case? > >> > >> I have : > >> > >> 10x 6TB Disk OSDs (data) > >> 2x 480G SSD > >> > >> Best, > > > > I'm still unsure with the size of the block.db and the wal. > > This seems to be relevant: > > http://lists.ceph.com/pipermail/ceph-users-ceph.com/2019-May/035086.html > > > > But it is also said that the pure WAL need just 1 GB of space. > > http://lists.ceph.com/pipermail/ceph-users-ceph.com/2019-August/036509.html > > > > So the conclusion would be to use 2*X(DB) + 1GB (WAL) if you put both on the same partition/LV. > > With X being on of 3GB, 30GB or 300GB. > > > > You have 10 OSDs. That means you should have 10 partitions/LVs for DBs & WALs. > > So, I don't have enough space on SSDs to do raid1, I must use 1 SSD for 5 disks. > > 5x64GB + 5x2GB should be good, shouldn't it? I'd put both on one LV/partition. > > And I still don't know if the ceph-ansible playbook can manage the LVM setup of shall I need to prepare all VG and LV before. > I did this manually before running the ansible-playbook. host_vars/host3.yml lvm_volumes: - data: /dev/sdb db: '1' db_vg: host-3-db - data: /dev/sdc db: '2' db_vg: host-3-db - data: /dev/sde db: '3' db_vg: host-3-db - data: /dev/sdf db: '4' db_vg: host-3-db … Lars _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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