LazyIO relaxes POSIX semantics. Buffered reads/writes are allowed even when a file is opened by multiple applications on multiple clients. Applications are responsible for managing cache coherency themselves.

Libcephfs supports LazyIO since nautilus release.

Enable LazyIO

LazyIO can be enabled by following ways.

  • client_force_lazyio option enables LAZY_IO globally for libcephfs and ceph-fuse mount.

  • ceph_lazyio(...) and ceph_ll_lazyio(...) enable LAZY_IO for file handle in libcephfs.

  • ioctl(fd, CEPH_IOC_LAZYIO, 1UL) enables LAZY_IO for file handle in

    ceph-fuse mount.