Useful nbdkit filters: the error filter

nbdkit --filter=error [...] error=EIO error-rate=10%

nbdkit --filter=error [...] error-rate=100% error-file=/tmp/inject

• Errors can be injected randomly with a uniform distribution.
• More usefully you can trigger errors from the presence of an error file.
• NBD protocol only supports: EPERM, EIO, ENOMEM, EINVAL, ENOSPC or ESHUTDOWN.