Just to add to the other comment: Ceph checksums data and metadata on every read/write operation. So even if you completely disable scrubbing, if data on a disk becomes corrupted, the OSD will detect it and the client will transparently fail over to another replica, rather than seeing bad data or an I/O error.

Scrubbing is only necessary to proactively detect bad sectors or silent corruption on infrequently-accessed data, so that you can replace the drive early without losing redundancy.