Den tis 5 apr. 2022 kl 11:26 skrev Ali Akil <ali-akil@xxxxxx>: > Hallo everybody, > I have two questions regarding bluestore. I am struggling to understand > the documentation :/ > > I am planning to deploy 3 ceph nodes with 10xHDDs for OSD data, Raid 0 > 2xSSDs for block.db with replication on host level. > > First Question : > Is it possible to deploy block.db on RAID 0 parition ? and Do i need to > backup the SSDs for block.db or the data will be replicated on the other > nodes ? Raid-0 on the block DB will mean that if one of the SSDs die, *all* of your OSDs are now lost. I would have each ssd be block.db for half the HDDs, so that no single failure causes the whole host to be lost. You would still lose half the OSDs, but the other half will still work if one of the SSDs die. > Second: > Under the BLOCK and BLOCK.DB <i am planning to deploy 3 ceph nodes with > HDDs for OSD, Raid 0 2xSSDs for block.db with replication on host level. > Do i need to backup the SSDs for block.db or the data will be replicated > on the other hosts?> section in the documentation is stated the i must > create volume groups and logical volumes, if i want to locate block.db > on another disk. It's not stated though the reason behind that. So why > it's not possible to just assign the block.db to the disk with E.g. > --block.db /dev/sdb without creating a logical volume? You can use --block.db /dev/sdb but it will use the whole of sdb for that one single OSD you are creating. In order to split a device as block.db for several OSDs, you should partition it and give each OSD one partition for block.db > Also what is the role for `ceph-volume lvm prepare` , if one should > create these logical volumes manually? The create pass is actually two tasks, prepare and activate. If you only want to do the first half, "prepare" is there so you can "activate" them later (i.e. set up systemd autostart and so on). -- May the most significant bit of your life be positive. _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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