Marcus Eriksson created CASSANDRA-5291:
------------------------------------------
Summary: Document how setting
internode_{send|recv}_buff_size_in_bytes might give you worse performance
Key: CASSANDRA-5291
URL: https://issues.apache.org/jira/browse/CASSANDRA-5291
Project: Cassandra
Issue Type: Improvement
Environment: linux
Reporter: Marcus Eriksson
Priority: Trivial
Attachments: 0001-clarify-so_sndbuf.patch
By setting SO_SNDBUF (or RCVBUF) (which is what
internode_{send|recv}_buff_size_in_bytes does), the actual buffers will be
limited by net.core.wmem_max and net.core.rmem_max which defaults to 131071 on
Debian, but if you dont set it, it will use net.ipv4.tcp_(w|r)mem which by
default has a max value of 4194304.
So, if you set internode_{send|recv}_buff_size_in_bytes, you will most likely
not get the buffer size you want unless you have also tweaked your OS.
Patch adds a few comments about this. Unsure if it should go in the config
file, but it should at least be mentioned somewhere
see:
/proc/sys/net/core/wmem_max
/proc/sys/net/core/rmem_max
/proc/sys/net/ipv4/tcp_wmem
/proc/sys/net/ipv4/tcp_rmem
man tcp
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
