.. _ceph-volume-lvm-batch: ``batch`` =========== The subcommand allows to create multiple OSDs at the same time given an input of devices. The ``batch`` subcommand is closely related to drive-groups. One individual drive group specification translates to a single ``batch`` invocation. The subcommand is based to :ref:`ceph-volume-lvm-create`, and will use the very same code path. All ``batch`` does is to calculate the appropriate sizes of all volumes and skip over already created volumes. All the features that ``ceph-volume lvm create`` supports, like ``dmcrypt``, avoiding ``systemd`` units from starting, defining bluestore or filestore, are supported. .. _ceph-volume-lvm-batch_auto: Automatic sorting of disks -------------------------- If ``batch`` receives only a single list of data devices and other options are passed , ``ceph-volume`` will auto-sort disks by its rotational property and use non-rotating disks for ``block.db`` or ``journal`` depending on the objectstore used. If all devices are to be used for standalone OSDs, no matter if rotating or solid state, pass ``--no-auto``. For example assuming :term:`bluestore` is used and ``--no-auto`` is not passed, the deprecated behavior would deploy the following, depending on the devices passed: #. Devices are all spinning HDDs: 1 OSD is created per device #. Devices are all SSDs: 2 OSDs are created per device #. Devices are a mix of HDDs and SSDs: data is placed on the spinning device, the ``block.db`` is created on the SSD, as large as possible. .. note:: Although operations in ``ceph-volume lvm create`` allow usage of ``block.wal`` it isn't supported with the ``auto`` behavior. This default auto-sorting behavior is now DEPRECATED and will be changed in future releases. Instead devices are not automatically sorted unless the ``--auto`` option is passed It is recommended to make use of the explicit device lists for ``block.db``, ``block.wal`` and ``journal``. .. _ceph-volume-lvm-batch_bluestore: Reporting ========= By default ``batch`` will print a report of the computed OSD layout and ask the user to confirm. This can be overridden by passing ``--yes``. If one wants to try out several invocations with being asked to deploy ``--report`` can be passed. ``ceph-volume`` will exit after printing the report. Consider the following invocation:: $ ceph-volume lvm batch --report /dev/sdb /dev/sdc /dev/sdd --db-devices /dev/nvme0n1 This will deploy three OSDs with external ``db`` and ``wal`` volumes on an NVME device. **pretty reporting** The ``pretty`` report format (the default) would look like this:: $ ceph-volume lvm batch --report /dev/sdb /dev/sdc /dev/sdd --db-devices /dev/nvme0n1 --> passed data devices: 3 physical, 0 LVM --> relative data size: 1.0 --> passed block_db devices: 1 physical, 0 LVM Total OSDs: 3 Type Path LV Size % of device ---------------------------------------------------------------------------------------------------- data /dev/sdb 300.00 GB 100.00% block_db /dev/nvme0n1 66.67 GB 33.33% ---------------------------------------------------------------------------------------------------- data /dev/sdc 300.00 GB 100.00% block_db /dev/nvme0n1 66.67 GB 33.33% ---------------------------------------------------------------------------------------------------- data /dev/sdd 300.00 GB 100.00% block_db /dev/nvme0n1 66.67 GB 33.33% **JSON reporting** Reporting can produce a structured output with ``--format json`` or ``--format json-pretty``:: $ ceph-volume lvm batch --report --format json-pretty /dev/sdb /dev/sdc /dev/sdd --db-devices /dev/nvme0n1 --> passed data devices: 3 physical, 0 LVM --> relative data size: 1.0 --> passed block_db devices: 1 physical, 0 LVM [ { "block_db": "/dev/nvme0n1", "block_db_size": "66.67 GB", "data": "/dev/sdb", "data_size": "300.00 GB", "encryption": "None" }, { "block_db": "/dev/nvme0n1", "block_db_size": "66.67 GB", "data": "/dev/sdc", "data_size": "300.00 GB", "encryption": "None" }, { "block_db": "/dev/nvme0n1", "block_db_size": "66.67 GB", "data": "/dev/sdd", "data_size": "300.00 GB", "encryption": "None" } ] Sizing ====== When no sizing arguments are passed, `ceph-volume` will derive the sizing from the passed device lists (or the sorted lists when using the automatic sorting). `ceph-volume batch` will attempt to fully utilize a device's available capacity. Relying on automatic sizing is recommended. If one requires a different sizing policy for wal, db or journal devices, `ceph-volume` offers implicit and explicit sizing rules. Implicit sizing --------------- Scenarios in which either devices are under-comitted or not all data devices are currently ready for use (due to a broken disk for example), one can still rely on `ceph-volume` automatic sizing. Users can provide hints to `ceph-volume` as to how many data devices should have their external volumes on a set of fast devices. These options are: * ``--block-db-slots`` * ``--block-wal-slots`` * ``--journal-slots`` For example, consider an OSD host that is supposed to contain 5 data devices and one device for wal/db volumes. However, one data device is currently broken and is being replaced. Instead of calculating the explicit sizes for the wal/db volume, one can simply call:: $ ceph-volume lvm batch --report /dev/sdb /dev/sdc /dev/sdd /dev/sde --db-devices /dev/nvme0n1 --block-db-slots 5 Explicit sizing --------------- It is also possible to provide explicit sizes to `ceph-volume` via the arguments * ``--block-db-size`` * ``--block-wal-size`` * ``--journal-size`` `ceph-volume` will try to satisfy the requested sizes given the passed disks. If this is not possible, no OSDs will be deployed. Idempotency and disk replacements ================================= `ceph-volume lvm batch` intends to be idempotent, i.e. calling the same command repeatedly must result in the same outcome. For example calling:: $ ceph-volume lvm batch --report /dev/sdb /dev/sdc /dev/sdd --db-devices /dev/nvme0n1 will result in three deployed OSDs (if all disks were available). Calling this command again, you will still end up with three OSDs and ceph-volume will exit with return code 0. Suppose /dev/sdc goes bad and needs to be replaced. After destroying the OSD and replacing the hardware, you can again call the same command and `ceph-volume` will detect that only two out of the three wanted OSDs are setup and re-create the missing OSD. This idempotency notion is tightly coupled to and extensively used by :ref:`drivegroups`.