| Message ID | 20230129102850.84731-9-faithilikerun@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add support for zoned device | expand |
On Sun, 29 Jan 2023 at 05:31, Sam Li <faithilikerun@gmail.com> wrote: > > Add the documentation about the zoned device support to virtio-blk > emulation. > > Signed-off-by: Sam Li <faithilikerun@gmail.com> > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> > Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> > Reviewed-by: Dmitry Fomichev <dmitry.fomichev@wdc.com> > --- > docs/devel/zoned-storage.rst | 43 ++++++++++++++++++++++++++ > docs/system/qemu-block-drivers.rst.inc | 6 ++++ > 2 files changed, 49 insertions(+) > create mode 100644 docs/devel/zoned-storage.rst This patch uses the old "zoned_host_device" BlockDriver name. Please update it to "host_device". It's probably a good idea to search the patches for zoned_host_device to find any other places that need to be updated. That can be done with git log -p master.. | grep zoned_host_device. > diff --git a/docs/devel/zoned-storage.rst b/docs/devel/zoned-storage.rst > new file mode 100644 > index 0000000000..03e52efe2e > --- /dev/null > +++ b/docs/devel/zoned-storage.rst > @@ -0,0 +1,43 @@ > +============= > +zoned-storage > +============= > + > +Zoned Block Devices (ZBDs) divide the LBA space into block regions called zones > +that are larger than the LBA size. They can only allow sequential writes, which > +can reduce write amplification in SSDs, and potentially lead to higher > +throughput and increased capacity. More details about ZBDs can be found at: > + > +https://zonedstorage.io/docs/introduction/zoned-storage > + > +1. Block layer APIs for zoned storage > +------------------------------------- > +QEMU block layer supports three zoned storage models: > +- BLK_Z_HM: The host-managed zoned model only allows sequential writes access > +to zones. It supports ZBD-specific I/O commands that can be used by a host to > +manage the zones of a device. > +- BLK_Z_HA: The host-aware zoned model allows random write operations in > +zones, making it backward compatible with regular block devices. > +- BLK_Z_NONE: The non-zoned model has no zones support. It includes both > +regular and drive-managed ZBD devices. ZBD-specific I/O commands are not > +supported. > + > +The block device information resides inside BlockDriverState. QEMU uses > +BlockLimits struct(BlockDriverState::bl) that is continuously accessed by the > +block layer while processing I/O requests. A BlockBackend has a root pointer to > +a BlockDriverState graph(for example, raw format on top of file-posix). The > +zoned storage information can be propagated from the leaf BlockDriverState all > +the way up to the BlockBackend. If the zoned storage model in file-posix is > +set to BLK_Z_HM, then block drivers will declare support for zoned host device. > + > +The block layer APIs support commands needed for zoned storage devices, > +including report zones, four zone operations, and zone append. > + > +2. Emulating zoned storage controllers > +-------------------------------------- > +When the BlockBackend's BlockLimits model reports a zoned storage device, users > +like the virtio-blk emulation or the qemu-io-cmds.c utility can use block layer > +APIs for zoned storage emulation or testing. > + > +For example, to test zone_report on a null_blk device using qemu-io is: > +$ path/to/qemu-io --image-opts -n driver=zoned_host_device,filename=/dev/nullb0 > +-c "zrp offset nr_zones" > diff --git a/docs/system/qemu-block-drivers.rst.inc b/docs/system/qemu-block-drivers.rst.inc > index dfe5d2293d..0b97227fd9 100644 > --- a/docs/system/qemu-block-drivers.rst.inc > +++ b/docs/system/qemu-block-drivers.rst.inc > @@ -430,6 +430,12 @@ Hard disks > you may corrupt your host data (use the ``-snapshot`` command > line option or modify the device permissions accordingly). > > +Zoned block devices > + Zoned block devices can be passed through to the guest if the emulated storage > + controller supports zoned storage. Use ``--blockdev zoned_host_device, > + node-name=drive0,filename=/dev/nullb0`` to pass through ``/dev/nullb0`` > + as ``drive0``. > + > Windows > ^^^^^^^ > > -- > 2.38.1 > >
Stefan Hajnoczi <stefanha@gmail.com> 于2023年2月6日周一 20:16写道： > > On Sun, 29 Jan 2023 at 05:31, Sam Li <faithilikerun@gmail.com> wrote: > > > > Add the documentation about the zoned device support to virtio-blk > > emulation. > > > > Signed-off-by: Sam Li <faithilikerun@gmail.com> > > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> > > Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> > > Reviewed-by: Dmitry Fomichev <dmitry.fomichev@wdc.com> > > --- > > docs/devel/zoned-storage.rst | 43 ++++++++++++++++++++++++++ > > docs/system/qemu-block-drivers.rst.inc | 6 ++++ > > 2 files changed, 49 insertions(+) > > create mode 100644 docs/devel/zoned-storage.rst > > This patch uses the old "zoned_host_device" BlockDriver name. Please > update it to "host_device". > > It's probably a good idea to search the patches for zoned_host_device > to find any other places that need to be updated. That can be done > with git log -p master.. | grep zoned_host_device. Sorry for missing that. Will do. > > > diff --git a/docs/devel/zoned-storage.rst b/docs/devel/zoned-storage.rst > > new file mode 100644 > > index 0000000000..03e52efe2e > > --- /dev/null > > +++ b/docs/devel/zoned-storage.rst > > @@ -0,0 +1,43 @@ > > +============= > > +zoned-storage > > +============= > > + > > +Zoned Block Devices (ZBDs) divide the LBA space into block regions called zones > > +that are larger than the LBA size. They can only allow sequential writes, which > > +can reduce write amplification in SSDs, and potentially lead to higher > > +throughput and increased capacity. More details about ZBDs can be found at: > > + > > +https://zonedstorage.io/docs/introduction/zoned-storage > > + > > +1. Block layer APIs for zoned storage > > +------------------------------------- > > +QEMU block layer supports three zoned storage models: > > +- BLK_Z_HM: The host-managed zoned model only allows sequential writes access > > +to zones. It supports ZBD-specific I/O commands that can be used by a host to > > +manage the zones of a device. > > +- BLK_Z_HA: The host-aware zoned model allows random write operations in > > +zones, making it backward compatible with regular block devices. > > +- BLK_Z_NONE: The non-zoned model has no zones support. It includes both > > +regular and drive-managed ZBD devices. ZBD-specific I/O commands are not > > +supported. > > + > > +The block device information resides inside BlockDriverState. QEMU uses > > +BlockLimits struct(BlockDriverState::bl) that is continuously accessed by the > > +block layer while processing I/O requests. A BlockBackend has a root pointer to > > +a BlockDriverState graph(for example, raw format on top of file-posix). The > > +zoned storage information can be propagated from the leaf BlockDriverState all > > +the way up to the BlockBackend. If the zoned storage model in file-posix is > > +set to BLK_Z_HM, then block drivers will declare support for zoned host device. > > + > > +The block layer APIs support commands needed for zoned storage devices, > > +including report zones, four zone operations, and zone append. > > + > > +2. Emulating zoned storage controllers > > +-------------------------------------- > > +When the BlockBackend's BlockLimits model reports a zoned storage device, users > > +like the virtio-blk emulation or the qemu-io-cmds.c utility can use block layer > > +APIs for zoned storage emulation or testing. > > + > > +For example, to test zone_report on a null_blk device using qemu-io is: > > +$ path/to/qemu-io --image-opts -n driver=zoned_host_device,filename=/dev/nullb0 > > +-c "zrp offset nr_zones" > > diff --git a/docs/system/qemu-block-drivers.rst.inc b/docs/system/qemu-block-drivers.rst.inc > > index dfe5d2293d..0b97227fd9 100644 > > --- a/docs/system/qemu-block-drivers.rst.inc > > +++ b/docs/system/qemu-block-drivers.rst.inc > > @@ -430,6 +430,12 @@ Hard disks > > you may corrupt your host data (use the ``-snapshot`` command > > line option or modify the device permissions accordingly). > > > > +Zoned block devices > > + Zoned block devices can be passed through to the guest if the emulated storage > > + controller supports zoned storage. Use ``--blockdev zoned_host_device, > > + node-name=drive0,filename=/dev/nullb0`` to pass through ``/dev/nullb0`` > > + as ``drive0``. > > + > > Windows > > ^^^^^^^ > > > > -- > > 2.38.1 > > > >
diff --git a/docs/devel/zoned-storage.rst b/docs/devel/zoned-storage.rst new file mode 100644 index 0000000000..03e52efe2e --- /dev/null +++ b/docs/devel/zoned-storage.rst @@ -0,0 +1,43 @@ +============= +zoned-storage +============= + +Zoned Block Devices (ZBDs) divide the LBA space into block regions called zones +that are larger than the LBA size. They can only allow sequential writes, which +can reduce write amplification in SSDs, and potentially lead to higher +throughput and increased capacity. More details about ZBDs can be found at: + +https://zonedstorage.io/docs/introduction/zoned-storage + +1. Block layer APIs for zoned storage +------------------------------------- +QEMU block layer supports three zoned storage models: +- BLK_Z_HM: The host-managed zoned model only allows sequential writes access +to zones. It supports ZBD-specific I/O commands that can be used by a host to +manage the zones of a device. +- BLK_Z_HA: The host-aware zoned model allows random write operations in +zones, making it backward compatible with regular block devices. +- BLK_Z_NONE: The non-zoned model has no zones support. It includes both +regular and drive-managed ZBD devices. ZBD-specific I/O commands are not +supported. + +The block device information resides inside BlockDriverState. QEMU uses +BlockLimits struct(BlockDriverState::bl) that is continuously accessed by the +block layer while processing I/O requests. A BlockBackend has a root pointer to +a BlockDriverState graph(for example, raw format on top of file-posix). The +zoned storage information can be propagated from the leaf BlockDriverState all +the way up to the BlockBackend. If the zoned storage model in file-posix is +set to BLK_Z_HM, then block drivers will declare support for zoned host device. + +The block layer APIs support commands needed for zoned storage devices, +including report zones, four zone operations, and zone append. + +2. Emulating zoned storage controllers +-------------------------------------- +When the BlockBackend's BlockLimits model reports a zoned storage device, users +like the virtio-blk emulation or the qemu-io-cmds.c utility can use block layer +APIs for zoned storage emulation or testing. + +For example, to test zone_report on a null_blk device using qemu-io is: +$ path/to/qemu-io --image-opts -n driver=zoned_host_device,filename=/dev/nullb0 +-c "zrp offset nr_zones" diff --git a/docs/system/qemu-block-drivers.rst.inc b/docs/system/qemu-block-drivers.rst.inc index dfe5d2293d..0b97227fd9 100644 --- a/docs/system/qemu-block-drivers.rst.inc +++ b/docs/system/qemu-block-drivers.rst.inc @@ -430,6 +430,12 @@ Hard disks you may corrupt your host data (use the ``-snapshot`` command line option or modify the device permissions accordingly). +Zoned block devices + Zoned block devices can be passed through to the guest if the emulated storage + controller supports zoned storage. Use ``--blockdev zoned_host_device, + node-name=drive0,filename=/dev/nullb0`` to pass through ``/dev/nullb0`` + as ``drive0``. + Windows ^^^^^^^