Den tors 16 mars 2023 kl 06:42 skrev Norman <norman.kern@xxxxxxx>: > Janne, > > Thanks for your reply. To reduce the cost of recovering OSDs while > WAL/DB device is down, maybe I have no > choice but add more WAL/DB devices. We do run one ssd-or-nvme for several OSD hdd drives and have not seen this as a problem in itself. For us, hdds still break down more often than the flash drives, though we choose flash drives with DWPD > 3 to make sure it can sustain a lot of writes over time. If you use (please don't!) cheap consumer ssds or whatever, then I think they will break down as often as spin drives, and having less or one such per hdd would be a wiser choice. Still, we try to build our clusters so we can handle a whole box falling off, which means 8 or 12 hdd drives are gone at the same time, so compared to this, having a single SSD take out 3-4-5 OSDs is not a complete disaster and well within the expected margins. One has to take into account that boxes will crash, drives will fail, processes will crash sometimes and so on, this is why we build clusters, so that other units can help share the load when (not if) it happens. -- 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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