DRBD 8.3 USER GUIDE PDF
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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Also see the degr-wfc-timeout parameter. This parameter usually does not need to be set, but it can be set to a value up to 10 MiB.
Take the copy of the current active server. If the address parameter is not provided, no connections to peers will be created by default. By default, csums-alg is unset. With DRBD, we refer to the devices inside a resource as volumes. Section path Parameters host name [ address [address-family] address ] [ port port-number ] Defines an endpoint for a connection.
The possible settings are: I’m guessing from all the testing i’ve just done that the 3rd node, since it’s a backup and possibly remote node is used when the first two nodes fail.
With this option you request that the automatic after-split-brain policies are used as long as the data sets of the nodes are somehow related. This handler can be used to call for administrator attention. This command will fail if the device is not part of a connected device pair. If it is too big it will be truncated. After the data sync has finished, create the meta-data on data-upper on alphafollowed by foxtrot.
This option is available since 9. Generate a new current-uuid and clear the dirty bitmap. The volume numbers in the various volume sections of a resource define which devices on which hosts form a replicated device. The node is currently primary, but lost the after-split-brain auto recovery procedure.
In case none wrote anything this policy uses a random decision to perform a “resync” of 0 blocks.
(5) — drbd-utils — Debian jessie-backports — Debian Manpages
When the –assume-clean option is given DRBD will skip the resync of the new storage. In case it decides the current secondary has the right data, it calls the “pri-lost-after-sb” handler on the current primary. Sync to the primary node is allowed, violating the assumption that data on a block device are stable for one of the nodes. By fencing we understand preventive measures to avoid situations where both uxer are primary and disconnected AKA split brain.
You only should use this option if you use a shared storage file system on top of DRBD. Values below 32K do not make sense. Then you might see “bio would need to, but cannot, be split: For example, in a three-node setup nodes A, B, C each with a single device, every node maintains one bitmap for each of its peers.
It turned out that there is at least one network stack that performs worse when one uses this hinting method. All nodes must be directly connected. When the index form of this parameter is used, multiple replicated devices can share the same metadata device, each using a separate index. It is possible that both devices of a connected DRBD device pair are secondary.
During on-line verification, the contents of every block on the local node are compared to those on the peer node. On a disconnected Primary device, this will set all bits in the out of sync bitmap.
Options can be overridden in a more specific gudieconnectiononor volume section. A known example is: In case the secondary node fails to complete a single write request for guuide times the timeoutit is expelled from the cluster.
If you need to use the device before it was ever connected to its peer, use this option to pass the size of the DRBD device to the driver. The disk state advances to diskless, as soon as the backing block device has finished all IO requests.
You can specify smaller or larger values. Please participate in DRBD’s online usage counter . Please note that the disk will be marked as failed until all pending IO requests where finished by the backing block device.
They 83 to do the initial handshake, so they know their sizes. The unit is tenths of a second. The use of this method can be disabled by the no-disk-barrier option.
It is on by default since DRBD 8. The fourth method is to not express write-after-write dependencies to the backing store at all, by also specifying no-disk-drain. Values smaller than 10 can lead to degraded performance.
Typically set to the same as –max-epoch-size. The handler is expected to reboot the machine, which puts it into secondary role. Each path section must contain exactly two host parameters. The address families ipv4ipv6ssocks Dolphin Interconnect Solutions’ “super sockets”sdp Infiniband Sockets Direct Protocoland sci are supported sci is an alias for ssocks.
At time of writing the only known drivers which have such a function are: The available policies are io-error and suspend-io. Once the dependencies are installed, download DRBD. This has at least two use cases, namely to skip the initial sync, and to reduce network bandwidth when starting in a single node configuration and then later re- integrating a remote site.
In case it decides the current secondary has the correct data, call the pri-lost-after-sb on the current primary.