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? 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. Best, -- Yoann Moulin EPFL IC-IT _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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