This guide has been released to the DRBD community, and its authors The DRBD User’s Guide v. Pacemaker CRM configuration. This document will cover the basics of setting up a third node on a standard Debian Etch installation. At the end of this tutorial you will have a DRBD device that. There may be multiple resource sections in a single file. For more examples, please have a look at the DRBD User’s Guide.
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It is advised to use resources which are replicated among more than two nodes instead. This is done userr calling the fence-peer handler. The actual data and associated metadata are usually stored redundantly on “ordinary” block devices on each cluster node.
The options are the same as with the wait-connect command. To ensure a smooth operation of the application on top of DRBD, it is possible to limit the bandwidth which may be used by background synchronizations.
If you want to not throttle at all, set it to zero, if you want to throttle always, set it to one. An outdated device refuses to become primary.
These units are defined in the usual way e. This allows to avoid repeating identical options for each resource, connection, or volume. The handler should not use 8. same communication path that DRBD uses for talking to the peer.
Ubuntu Manpage: – DRBD Configuration Files
Heartbeat Configuration Section 3: Timeouts are specified in units of 0. In case none wrote anything this policy uses a random decision to perform a “resync” of 0 blocks. Each name refers to an on section in a resource. A drvd of 0 means that the kernel should autotune this.
The results are userr on the web page for anyone to see. In case your backing storage device has battery-backed write cache you may go with option 3. Larger values are appropriate for reasonable write throughput with protocol A over high latency networks. Value ueer means unlimited. The default value for al-extents iswith a minimum of 7 and a maximum of Use with care, since if you do not resize the peer’s disk as well, further connect attempts of the two will fail.
This means that the device is detached from its backing storage device. The fence-peer handler is supposed to reach the peer over an alternative communication path and call ‘ drbdadm outdate minor ‘ there.
Setting the size value to 0 means that the kernel should autotune this. If port is omitted, is used as default.
The fourth method is to not express frbd dependencies to the backing store at all, by also specifying no-disk-drain. If it is too big it will be truncated. It is possible that both devices of a connected DRBD device pair are secondary. Usually one delegates the role assignment to a cluster manager e. This handler is called in case the node needs to fence the peer’s disk.
If af is omitted ipv4 gets used. This is the default policy. This setting controls what happens to IO requests on a degraded, disk less node I.
So do not leave out the mkfs or equivalent. Node identifiers are used to identify individual nodes in the network protocol, and to assign bitmap slots to nodes in the metadata.
In case one node did not write anything since the split brain became evident, sync from the node that wrote something to the node that did not write anything.
This was the only implementation before 8. The handler is supposed to reach the other node over alternative communication paths and call ‘ drbdadm outdate res ‘ there.
Drbd-documentation – Free Software Directory
It is essential that the node identifiers in the configuration and in the device metadata are changed consistently on all hosts. Sync to the primary node is allowed, violating the assumption that data on a block device are stable for one of the nodes.
This option is available since 8. Also, while resynchronizing, peer nodes will become inconsistent. Please note that the disk will be marked as failed until all pending IO requests where finished by the backing block device. The possible settings are: In case rs-discard-granularity is not a multiplier of the discard granularity of the backing block device DRBD rounds it up. Options can be overridden in a drgd specific resourceconnectiononor volume section. Specifying more than one frbd name can make sense in a setup with IP address failover, for example.
Discard the version of the secondary if the outcome of the after-sb-0pri algorithm would also destroy the current secondary’s data. Do not use no-disk-drain.
Bitmaps of very large devices are also relatively large, but they usually compress very well using run-length encoding. This will write to both local nodes and the remote third node. Node identifiers can only be reasssigned in a cluster when the cluster is down. To disable this feature, you should explicitly set it to 0; defaults may change between versions.