Different ways to get information such as default values, units of measurement, and accepted value ranges, for DRBD configuration file options
Getting DRBD Options Information by Using the Manual Page
If you are using DRBD® 9, you can use the `man drbd.conf-9.0` command to get detailed information about options that you can use within DRBD configuration files.
An example entry from the manual page for the ping interval option is:
ping-int interval
When the TCP/IP connection to a peer is idle for more than
ping-int seconds, DRBD will send a keep-alive packet to make
sure that a failed peer or network connection is detected
reasonably soon. The default value is 10 seconds, with a
minimum of 1 and a maximum of 120 seconds. The unit is seconds.
Getting DRBD Options Information by Using `drbdsetup`
Another way that you can get information, such as default values, value ranges, and units of
measurement, for DRBD options, is by using the `drbdsetup` command.
Getting DRBD Options Information from the `xml-help` Command
The `drbdsetup xml-help` command is used to generate output for manual pages. You can use it as an alternative way to see information about DRBD options, in XML format. This can be useful if you want to quickly get default values, units of measurement, and value ranges, for DRBD options, without having to look at surrounding text in the manual page. However, this way will not show you the context for using DRBD options that the manual page might show.
The `xml-help` command is available for the following types of DRBD configuration file options:
# drbdsetup xml-help resource-options
# drbdsetup xml-help peer-device-options
# drbdsetup xml-help net-options
# drbdsetup xml-help disk-options
For example:
# drbdsetup xml-help net-options
[...]
<option name="ping-int" type="numeric">
<min>1</min>
<max>120</max>
<default>10</default>
<unit_prefix>1</unit_prefix>
<unit>seconds</unit>
</option>
[...]
Getting Default DRBD Options for a Configured DRBD Resource
If you have already configured a DRBD resource, either manually or by using LINSTOR®, you can get the resource's DRBD options values by using the `drbdsetup show --show-defaults` command. You can run the command and add a configured DRBD resource's name as an argument to show the resource's running configuration, including DRBD options and their default values (if the options were not specified in the DRBD configuration file itself). If you enter the command without specifying a DRBD resource, then the command will show configuration files for all configured DRBD resources on the node.
This command is useful to learn which DRBD options are implicitly configured along with their default values. The command output will also show in which section of the DRBD configuration file options occur: options (global), disk, or net. Unlike the other ways of getting DRBD options information mentioned in this article, the `drbdsetup show --show-defaults` will not show the range of acceptable values for the DRBD options.
For example:
# drbdsetup show --show-defaults testres
resource "testres" {
options {
cpu-mask ""; # default
on-no-data-accessible io-error; # default
auto-promote yes; # default
peer-ack-window 4096s; # bytes, default
peer-ack-delay 100; # milliseconds, default
twopc-timeout 300; # 1/10 seconds, default
twopc-retry-timeout 1; # 1/10 seconds, default
auto-promote-timeout 20; # 1/10 seconds, default
max-io-depth 8000; # default
quorum majority;
on-no-quorum io-error;
quorum-minimum-redundancy off; # default
on-suspended-primary-outdated disconnect; # default
}
_this_host {
node-id 0;
volume 0 {
device minor 1000;
disk "/dev/drbdpool/testres_00000";
meta-disk internal;
disk {
size 0s; # bytes, default
on-io-error detach; # default
disk-barrier no; # default
disk-flushes yes; # default
disk-drain yes; # default
md-flushes yes; # default
[...]
}
[...]
}
Getting DRBD Options Information by Using LINSTOR's Help Command
If you are using LINSTOR, you can use the output from the `linstor <LINSTOR_object> drbd-options --help` (or `drbd-peer-options --help`) command to get information about DRBD options.
For example:
# linstor resource-definition drbd-options --help
[...]
--ping-int PING_INT Range: [1, 120]; Default: 10; Unit: seconds
[...]
TIP: The command `linstor <LINSTOR_object> opt --help` shows the same output as `linstor <LINSTOR_object> drbd-options --help`, if you are interested in saving some keystrokes.
Searching for a Specific DRBD Option in Command Output
For the LINSTOR `--help` and the `drbdsetup` commands, it is useful to pipe the output through the `less` command. You can then use the forward slash key (`/`) to search for keywords to find the DRBD option that you are interested in.
Created by MAT, 2023-03-13
Reviewed by DJV 2023-03-14