Return
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Title
How to configure so-rcvbuf() -
Description
The so-rcvbuf() receive buffer is used by TCP and UDP to hold received data until it is forwarded to the destination. However, increasing this value alone may not increase the size of the buffer and message loss may occur.
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Cause
By Design -
Resolution
The so-rcvbuf() has a corresponding entry called net.core.rmem_max in /etc/sysctl.conf
From the Linux kernel side the net.core.rmem_max parameter limits the values so-rcvbuf() can take.
For RHEL the default net.core.rmem_max value is 262144 bytes and therefore may not be listed in sysctl.conf as it is a default. Other operating systems may have different default values.
To increase the net.core.rmem_max value add the following line or modify the existing one in /etc/sysctl.conf.net.core.rmem_max = <New Value>
The following guidelines should be noted when setting the net.core.rmem_max value.- net.core.rmem_max should be at least twice as big as so-rcvbuf()
- The largest safe value net.core.rmem_max may take is 2147483647 (2GB-1)
- The largest value so-rcvbuf() may take is 1073741823 (1GB-1)
From the admin guide.++++++++
Note that on certain platforms, ……. even low message load (~200 messages per second) can result in message loss, unless the so-rcvbuf() option of the source is increased. In such cases, you will need to increase the net.core.rmem_max parameter of the host (for example, to 1024000), but do not modify net.core.rmem_default parameter.
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For details on how to performance tune UDP log reception please see the following KB article.
https://support.oneidentity.com/kb/4283052/how-to-performance-tune-udp-log-reception-of-syslog-ng-udp-packets-are-getting-dropped-receiving-packet-receive-and-buffer-errors-4283052
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Additional Information
If you require assistance with the so-rcvbuf() configuration, then please contact One Identity Professional Services. https://support.oneidentity.com/professional-services-product-select