====== NEO4J Availability ======
High availability to neo4j: Clients -> HAproxy -> neo4j servers


===== Linux preformance =====
<file | /etc/security/limits.conf>
neo4j   soft    nofile  40000
neo4j   hard    nofile  40000
</file>


<code bash>
echo 'deadline' > /sys/block/sda/queue/scheduler
cat               /sys/block/sda/queue/scheduler
noop [deadline] cfq
</code>



===== Neo4J configuration =====
<file | /.../neo4j/conf/neo4j-server.properties>
################################################################
# Neo4j
#
# neo4j-server.properties - runtime operational settings
#
################################################################

#***************************************************************
# Server configuration
#***************************************************************

org.neo4j.server.database.location=data/graph.db
org.neo4j.server.db.tuning.properties=conf/neo4j.properties
org.neo4j.server.database.mode=HA
org.neo4j.server.webserver.address=0.0.0.0
dbms.security.auth_enabled=false


org.neo4j.server.webserver.port=7474
org.neo4j.server.webserver.https.enabled=true
org.neo4j.server.webserver.https.port=7473
dbms.security.tls_certificate_file=conf/ssl/snakeoil.cert
dbms.security.tls_key_file=conf/ssl/snakeoil.key
org.neo4j.server.webserver.https.keystore.location=data/keystore
org.neo4j.server.http.log.enabled=false
org.neo4j.server.http.log.config=conf/neo4j-http-logging.xml
org.neo4j.server.webadmin.rrdb.location=data/rrd
dbms.browser.remote_content_hostname_whitelist=http://guides.neo4j.com,https://guides.neo4j.com,http://localhost,https://localhost
dbms.security.allow_outgoing_browser_connections=true
</file>
<file | /.../neo4j/conf/neo4j.properties>
################################################################
# Neo4j
#
# neo4j.properties - database tuning parameters
#
################################################################
online_backup_enabled=true
online_backup_server=192.168.168.33:6362
ha.server_id=1
ha.initial_hosts=192.168.168.33:5001,192.168.168.34:5001
ha.cluster_server=192.168.168.33:5001
ha.server=192.168.168.33:6001
ha.pull_interval=10
</file>

==== HAproxy ====

<file | /etc/haproxy/haproxy-neo4j.cfg>
global
  daemon
  maxconn 384

defaults
  mode http
  timeout connect 5000ms
  timeout client 50000ms
  timeout server 50000ms

frontend http-in
  bind *:7777
  default_backend neo4j

backend neo4j
  option httpchk GET /db/manage/server/ha/available
  server s1 192.168.168.33:7474 maxconn 128 check
  server s2 192.168.168.34:7474 maxconn 128 check
  server s3 192.168.168.35:7474 maxconn 128 check

listen admin
  bind *:7770
  stats enable
</file>

<code bash>
yum install haproxy
haproxy -f /etc/haproxy/haproxy-neo4j.cfg
</code>

See: http://192.168.168.33:7770/haproxy?stats