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. On 2023/3/15 15:04, Janne Johansson wrote:
hi, everyone, I have a question about repairing the broken WAL/DB device.
I have a cluster with 8 OSDs, and 4 WAL/DB devices(1 OSD per WAL/DB device), and hwo can I repair the OSDs quickly if
one WAL/DB device breaks down without rebuilding the them? Thanks. I think this is one of the parameters one has to take into account when doing the risk assessment of using one fast device for many slow data devices when setting up OSDs. If/when the WAL/DB breaks, you should be prepared to rebuild the OSDs related to the broken WAL/DB device. From what I remember, the WAL+DB contains things that actually are vital for the OSD, so it's probably not a matter of running some magic command and recreate the information from the data device.
For old filestore journals, one could somewhat live with a broken journaling device and recreate that, but I don't think that is true for bluestore DBs.