docs/devel/zoned-storage.rst

2 zoned-storage
10 https://zonedstorage.io/docs/introduction/zoned-storage
13 -------------------------------------
15 - BLK_Z_HM: The host-managed zoned model only allows sequential writes access
16 to zones. It supports ZBD-specific I/O commands that can be used by a host to
18 - BLK_Z_HA: The host-aware zoned model allows random write operations in
20 - BLK_Z_NONE: The non-zoned model has no zones support. It includes both
21 regular and drive-managed ZBD devices. ZBD-specific I/O commands are not
27 a BlockDriverState graph(for example, raw format on top of file-posix). The
29 the way up to the BlockBackend. If the zoned storage model in file-posix is
36 --------------------------------------
38 like the virtio-blk emulation or the qemu-io-cmds.c utility can use block layer
41 For example, to test zone_report on a null_blk device using qemu-io is::
43   $ path/to/qemu-io --image-opts -n driver=host_device,filename=/dev/nullb0 -c "zrp offset nr_zones"
45 To expose the host's zoned block device through virtio-blk, the command line
46 can be (includes the -device parameter)::
48   -blockdev node-name=drive0,driver=host_device,filename=/dev/nullb0,cache.direct=on \
49   -device virtio-blk-pci,drive=drive0
51 Or only use the -drive parameter::
53   -driver driver=host_device,file=/dev/nullb0,if=virtio,cache.direct=on
56 (1) Using virtio-scsi: --device scsi-block allows for the passing through of
58 (2) PCI device pass-through: While NVMe ZNS emulation is available for testing
59 purposes, it cannot yet pass through a zoned device from the host. To pass on
60 the NVMe ZNS device to the guest, use VFIO PCI pass the entire NVMe PCI adapter
61 through to the guest. Likewise, an HDD HBA can be passed on to QEMU all HDDs