drbdmeta

8 System Administration

drbdmeta

Manipulate the DRBD on-disk metadata

          drbdmeta
          --force
          --ignore-sanity-checks

            device

            v06 minor
            v07 meta_dev index
            v08 meta_dev index
            v09 meta_dev index

            command

            cmd args

## Description

The `drbdmeta` utility is used for creating, displaying, and modifying DRBD's on-disk metadata. Users usually interact with the `drbdadm` utility, which provides a more high-level interface to DRBD than `drbdmeta`. (See `drbdadm`'s `--dry-run` option to see how `drbdadm` uses `drbdmeta`.)

This utility can only be used on devices which are not currently in use by the kernel.

The first argument (`device`) specifies the drbd device associated with a volume, or - if no device is associated with that volume. If the drbd device is specified, the `drbdmeta` utility makes sure that the drbd device does not currently have a volume attached to prevent meta-data of an active volume from being destroyed.

The second argument specifies the metadata version to use (v06, v07, v08, v09). In most metadata versions, the third argument (`meta_dev`) specifies the device which contains the metadata; this argument can be the same as `device`. The fourth argument (`index`) can be one of the keywords `internal` (for internal metadata), `flex-internal` (in v07 for variable-sized metadata; v07 otherwise defaults to fixed-size internal metadata), `flex-external` (for variable-sized external metadata), or a numeric matadata index (for fixed-size external metadata). See the `meta-disk` parameter in

drbd.conf

5 .

## Options

--force

- Assume yes as the answer to all questions drbdmeta would ask.

--ignore-sanity-checks

- Normally, `drbdmeta` performs some sanity checks before writing to the metadata device: for example, if the device appears to contain a file system, it refuses to destroy the file system by writing into it. Use this option to ignore these checks.

## Commands

`create-md` `--peer-max-bio-size=``val` (metadata versions v06, v07, and v08)

`create-md` number-of-bitmap-slots `--peer-max-bio-size=``val` `--initialize-bitmap-mode=``{automatic|zeroout|pwrite|skip}` `--al-stripes=``val` `--al-stripe-size-kB=``val` (metadata version v09)

- Initialize the metadata. This is necessary before a DRBD resource can be attached. If `drbdmeta` finds an older version of DRBD metadata on the device, it asks if the format should be converted.

  When `drbdadm` calls `drbdmeta`'s `create-md` command for a device, it sets the `number-of-bitmap-slots` argument to the number of peers in the resource. To reserve additional bitmap slots (which allows to add more peers in the future), call `drbdmeta` directly instead.

  When a device is used before being connected to its peers the first time, DRBD assumes that peers can only handle 4 KiB requests by default. The `--peer-max-bio-size` option allows to set more optimistic values; use this if the versions of DRBD that this device will connect to are known. DRBD supports a maximum bio size of 32 KiB since version 8.3.8, of 128 KiB since version 8.3.9, and of 1 MiB since version 8.4.0.

  By default, we explicitly initialize the bitmap area to all zero. With `--initialize-bitmap-mode` you can chose to only try the fast method (`zeroout`, try ioctl BLKZEROOUT only), only use explicit `pwrite` calls, or `skip` this bitmap initialization phase completely. If you intend to do an initial full sync anyways, you can use `skip` to leave the bitmap initialization to the kernel. This can make a noticable difference when initializing huge volumes. Default is `automatic`, which is zeroout with an implicit fallback to pwrite.

  If you want to use more than 6433 activity log extents, or live on top of a spriped RAID, you may specify the number of stripes (`--al-stripes`, default 1), and the stripe size (`--al-stripe-size-kB`, default 32). To just use a larger linear on-disk ring-buffer, leave the number of stripes at 1, and increase the size only: `drbdmeta 0 v08 /dev/vg23/lv42 internal create-md --al-stripe-size 1M`

  To avoid a single "spindle" from becoming a bottleneck, increase the number of stripes, to achieve an interleaved layout of the on-disk activity-log transactions. What you give as "stripe-size" should be what is a.k.a. "chunk size" or "granularity" or "strip unit": the minimum skip to the next "spindle". `drbdmeta 0 v08 /dev/vg23/lv42 internal create-md --al-stripes 7 --al-stripe-size 64`

`get-gi` `--node-id=``id`

- Show the data generation identifiers for a device on a particular connection. DRBD version 9.0.0 and beyond support multiple peers; use the `node-id` option to define which peer's data generation identifiers to show.

`show-gi` `--node-id=``id`

- Similar to `get-gi`, but with explanatory information.

`dump-md`

- Dump the metadata of a device in text form, including the bitmap and activity log.

`outdate`

- Mark the data on a lower-level device as outdated. See

  drbdsetup

  8 for details.

`dstate`

- Show the current disk state of a lower-level device.

`check-resize`

- Examine the device size of a lower-level device and its last known device size (saved in `/var/lib/drbd/drbd-minor-`minor`.lkbd` by `drbdsetup check-resize`). For internal metadata, if the size of the lower-level device has changed and the metadata can be found at the previous position, move the metadata to the new position at the end of the block device.

`apply-al`

- Apply the activity log of the specified device. This is necessary before the device can be attached by the kernel again.

`repair-md` `--tentative`

- Repair known problems in metadata. Only problems that can be automatically fixed in a safe manner will be repaired. When `--tentative` is set, the metadata will only be checked, it will not be changed.

## Expert commands

The `drbdmeta` utility can be used to fine tune metdata. Please note that this can lead to destroyed metadata or even silent data corruption; use with great care only.

`set-gi` `gi` `--node-id=``id`

- Set the generation identifiers. The `gi` argument is a generation counter for the v06 and v07 formats, and a set of UUIDs for v08 and beyond. Accepts the same syntax as in the `get-gi` output. DRBD version 9.0.0 and beyond support multiple peers; use the `--node-id` option to define which peer's data generation identifiers to set.

`restore-md` `dump_file`

- Replace the metadata on the device with the contents of `dump_file`. The dump file format is defined by the output of the `dump-md` command.

## Version

This document was revised for version 9.0.0 of the DRBD distribution.

## Author

Written by Philipp Reisner philipp.reisner@linbit.com and Lars Ellenberg lars.ellenberg@linbit.com.

## Reporting Bugs

Report bugs to drbd-user@lists.linbit.com.

## Copyright

Copyright 2001-2008,2012 LINBIT Information Technologies, Philipp Reisner, Lars Ellenberg. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

## See Also

drbdadm

8

drbd.conf

5