QEMU-NBD(8) QEMU QEMU-NBD(8) (NAME) qemu-nbd - Network Block Device QEMU (SYNOPSIS) qemu-nbd [OPTION]... filename qemu-nbd -L [OPTION]... qemu-nbd -d dev (DESCRIPTION) QEMU NBD. : o /dev/nbdX QEMU ( ). o NBD . (OPTIONS) filename --image-opts . dev NBD . --object type,id=ID,... type ID . qemu(1) . secret / tls-creds TLS qemu-nbd . -p, --port=PORT TCP ( 10809). -o, --offset=OFFSET ( ) . -b, --bind=IFACE ( 0.0.0.0). -k, --socket=PATH PATH. --image-opts filename . -f format= . -f, --format=FMT FMT . -r, --read-only . -A, --allocation-depth qemu:allocation-depth NBD_OPT_SET_META_CONTEXT. -B, --bitmap=NAME filename qcow2 NAME qemu:dirty-bitmap:NAME NBD_OPT_SET_META_CONTEXT . -s, --snapshot filename backing_file=filename . -l, --load-snapshot=SNAPSHOT_PARAM filename SNAPSHOT_PARAM snapshot.id=[ID],snapshot.name=[NAME] [ID_OR_NAME]. --cache=CACHE . : none writeback () writethrough directsync unsafe. -drive cache=... . -n, --nocache --cache=none. --aio=AIO / threads () native ( ) io_uring ( +5.1). --discard=DISCARD discard ( trim unmap) . DISCARD ignore ( off) unmap ( on) . ignore . --detect-zeroes=DETECT_ZEROES . DETECT_ZEROES off on unmap . unmap unmap DISCARD unmap . off . -c, --connect=DEV filename NBD DEV ( ). -d, --disconnect DEV ( ). -e, --shared=NUM NUM ( 1) 0 . -t, --persistent . -x, --export-name=NAME NBD ( ). -D, --description=DESCRIPTION NBD . --handshake-limit=N N ( 10) 0 . -L, --list NBD . ( --export-name --offset ...) . --tls-creds=ID TLS TLS --object . --tls-hostname=hostname x509 TLS NBD . . NBD localhost --tls-hostname NBD . NBD UNIX . NBD --list . --fork . --pid-file=PATH . --tls-authz=ID qauthz --object . x509 . -v, --verbose . qemu-nbd --fork -c STDERR . -h, --help . -V, --version . -T, --trace [[enable=]PATTERN][,events=FILE][,file=FILE] . [enable=]PATTERN PATTERN ( globbing). QEMU simple log ftrace . -trace . -trace help . events=FILE FILE. ( trace-events-all ) globbing . QEMU simple log ftrace . file=FILE FILE. QEMU simple . (EXAMPLES) 10809 qcow2 TLS ( ) . : qemu-nbd -f qcow2 file.qcow2 10810 X.509 raw 'subset': qemu-nbd \ --object tls-creds-x509,id=tls0,endpoint=server,dir=/path/to/qemutls \ --object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,\ O=Example Org,,L=London,,ST=London,,C=GB' \ --tls-creds tls0 --tls-authz auth0 \ -t -x subset -p 10810 \ --image-opts driver=raw,offset=1M,size=1M,file.driver=file,file.filename=file.raw : qemu-nbd --fork --persistent --shared=5 --socket=/path/to/sock \ --read-only --format=qcow2 file.qcow2 qcow2 /dev/nbd0 ( /dev/nbd0p1 ) . qemu-nbd /dev/nbd NBD modprobe nbd . : (mount) - . qemu-nbd -c /dev/nbd0 -f qcow2 file.qcow2 qemu-nbd -d /dev/nbd0 () 10809 PSK: qemu-nbd \ --object tls-creds-psk,id=tls0,dir=/tmp/keys,username=eblake,endpoint=client \ --tls-creds tls0 -L -b remote.example.com (SEE ALSO) qemu(1), qemu-img(1) (AUTHORS) Anthony Liguori (COPYRIGHT) 2026, The QEMU Project Developers 11.1.1 August 28, 2026 QEMU-NBD(8)