Ceph

Mmm, I'm not sure we want to do the naive thing (write a file and fsync) on every election as that will slow them down a lot in the common case. Probably if we just check store accessibility on bootup, flip a flag if we ever fail one, and check for it on every election?

Greg Farnum wrote:

Mmm, I'm not sure we want to do the naive thing (write a file and fsync) on every election as that will slow them down a lot in the common case. Probably if we just check store accessibility on bootup, flip a flag if we ever fail one, and check for it on every election?

Yeah I think a check on boot is sufficient.

Can we have a bit more context please? What's the rationale behind this? The monitor should not start if leveldb is not open, and since it's not open it's not writeable. Is this in case the disk is full or the fs is read-only? Or something else I'm missing?

please note that the background compaction fails, if leveldb can not create new tables or remove merged tables.

so, if we "chmod -w store.db". and leveldb complains in this case, but it does not return error on Write() unless "leveldb_paranoid" is true, but this option is "false" by default. so "failed to write to db" assertion is not triggered, even if compaction fails with the default settings.