Aborted Connections with maxscale 1.2.0 and MariaDB 10.1.8

[Simon Hanmer]

Hi hoping someone might be able to help - we have a 3 node Galera cluster which we upgraded to MariaDB 10.1.8 a week or so again. We've been trying to import from our live servers using data generated via mysqldump, but our import is failing.

Typically we get a message similar to "ERROR 2003 (HY000) at line 153: Lost connection to backend server." from maxscale and on checking the MariaDB logs we see errors like

 2015-11-06 15:21:00 140644199458560 [Warning] Aborted connection 397 to db: 'unconnected' user: 'maxscale_dba' host: 'cisvirmdb-max02.int.dur.ac.uk' (Unknown error)

I've seen some of the messages around ulimits but I've checked and we're running with effectively unlimited (check /proc/<mysqld_pid>/limits reports 65535).

This had been running on MariaDB-Galera-server (10.0.21) and Maxscale (1.2.0)

Our Maxscale.cnf file looks like:

[maxscale]

threads=4

log_debug=1

log_trace=1

[Splitter Service]

type=service

router=readwritesplit

servers=db1,db2,db3

user=maxscale_user

passwd=****

max_slave_connections=100%

router_options=slave_selection_criteria=LEAST_CURRENT_OPERATIONS

strip_db_esc=1

[Splitter Listener]

type=listener

service=Splitter Service

protocol=MySQLClient

port=3306

[db1]

address=10.10.1.41

type=server

port=3306

protocol=MySQLBackend

[db2]

address=10.10.1.42

type=server

port=3306

protocol=MySQLBackend

[db3]

address=10.10.1.43

type=server

port=3306

protocol=MySQLBackend

[Galera Monitor]

type=monitor

module=galeramon

servers=db1,db2,db3

user=maxscale_user

passwd=****

monitor_interval=8000

backend_connect_timeout=3

backend_read_timeout=1

backend_write_timeout=2

# galeramon specific options

disable_master_failback=0

available_when_donor=0

disable_master_role_setting=0

[CLI]

type=service

router=cli

[CLI Listener]

type=listener

service=CLI

protocol=maxscaled

address=localhost

port=6603

and the /etc/my.cnf.d/server.cnf files are like:

[client]

port = 3306

socket = /var/lib/mysql/mysql.sock

[galera]

innodb_autoinc_lock_mode = 2

innodb_doublewrite = 1

innodb_flush_log_at_trx_commit = 2

innodb_locks_unsafe_for_binlog = 1

innodb_log_file_size = 256M

open_files_limit = 40960

query_cache_type = 0

#wsrep_causal_reads = ON

wsrep_cluster_address = gcomm://db1,db2,db3

wsrep_cluster_name = galera_cluster

wsrep_node_name = db1

wsrep_on = ON

wsrep_provider = /usr/lib64/galera/libgalera_smm.so

wsrep_sst_auth = ****:****

wsrep_sst_method = xtrabackup

wsrep_sst_receive_address = db1

#wsrep_sync_wait = 7

[isamchk]

key_buffer_size = 16M

[mysqld]

basedir = /usr

bind-address = 0.0.0.0

binlog_format = ROW

character_set_server = utf8mb4

collation_server = utf8mb4_unicode_520_ci

datadir = /var/lib/mysql

default-storage-engine = innodb

expire_logs_days = 10

ignore_db_dirs = lost+found

ignore_db_dirs = backups

innodb_file_per_table = 1

key_buffer_size = 16M

log-error = /var/log/mariadb/mariadb.log

log_warnings=3

max_allowed_packet = 64M

max_binlog_size = 100M

max_connections = 151

myisam_recover_options = BACKUP #SIMON

pid-file = /var/lib/mysql/db1.pid

port = 3306

query_cache_limit = 1M

query_cache_size = 0

skip-external-locking

socket = /var/lib/mysql/mysql.sock

ssl = false

ssl-ca = /etc/mysql/cacert.pem

ssl-cert = /etc/mysql/server-cert.pem

ssl-key = /etc/mysql/server-key.pem

thread_cache_size = 8

thread_stack = 256K

tmpdir = /tmp

user = mysql

[mysqld_safe]

log-error = /var/log/mariadb/mariadb.log

nice = 0

socket = /var/lib/mysql/mysql.sock

[mysqldump]

max_allowed_packet = 16M

quick

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