Install mysqltuner with 'yum install mysqltuner -y' and then check your mysql setting with running 'mysqltuner --user root --pass yourmysqlrootpassword'. Get this password from /usr/local/lxlabs/kloxo/etc/slavedb/dbadmin file.
I just got the error again so I reboot it the server and read your post after. I followed the give steps and I got this result on 'mysqltuner --user root --pass yourmysqlrootpassword' :
>> MySQLTuner 1.1.1 - Major Hayden <major@mhtx.net>
>> Bug reports, feature requests, and downloads at http://mysqltuner.com/
>> Run with '--help' for additional options and output filtering
[OK] Logged in using credentials passed on the command line
-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.5.42
[OK] Operating on 64-bit architecture
-------- Storage Engine Statistics -------------------------------------------
[--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in MyISAM tables: 4M (Tables: 137)
[--] Data in InnoDB tables: 28M (Tables: 91)
[--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
[!!] Total fragmented tables: 91
-------- Security Recommendations -------------------------------------------
[!!] User 'root' has no password set.
[!!] User 'root' has no password set.
[!!] User 'root' has no password set.
[!!] User '' has no password set.
[!!] User '' has no password set.
-------- Performance Metrics -------------------------------------------------
[--] Up for: 2m 24s (412 q [2.861 qps], 19 conn, TX: 1M, RX: 50K)
[--] Reads / Writes: 96% / 4%
[--] Total buffers: 272.0M global + 4.2M per thread (151 max threads)
[!!] Maximum possible memory usage: 913.8M (91% of installed RAM)
[OK] Slow queries: 0% (0/412)
[OK] Highest usage of available connections: 3% (5/151)
[OK] Key buffer size / total MyISAM indexes: 64.0M/1.1M
[!!] Key buffer hit rate: 0.0% (3 cached / 3 reads)
[OK] Query cache efficiency: 55.5% (206 cached / 371 selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 39 sorts)
[!!] Temporary tables created on disk: 30% (6 on disk / 20 total)
[OK] Thread cache hit rate: 73% (5 created / 19 connections)
[OK] Table cache hit rate: 86% (46 open / 53 opened)
[OK] Open file limit used: 0% (32/65K)
[OK] Table locks acquired immediately: 100% (216 immediate / 216 locks)
[OK] InnoDB data size / buffer pool: 28.0M/128.0M
-------- Recommendations -----------------------------------------------------
General recommendations:
Run OPTIMIZE TABLE to defragment tables for better performance
MySQL started within last 24 hours - recommendations may be inaccurate
Reduce your overall MySQL memory footprint for system stability
Enable the slow query log to troubleshoot bad queries
When making adjustments, make tmp_table_size/max_heap_table_size equal
Reduce your SELECT DISTINCT queries without LIMIT clauses
Variables to adjust:
*** MySQL's maximum memory usage is dangerously high ***
*** Add RAM before increasing MySQL buffer variables ***
tmp_table_size (> 32M)
max_heap_table_size (> 64M)
It seems like 1Gb RAM its not enough for 3 Wordpress websites.. I upgrade it the RAM to 4Gb. Anything else I should do ?
Result after RAM upgrade:
>> MySQLTuner 1.1.1 - Major Hayden <major@mhtx.net>
>> Bug reports, feature requests, and downloads at http://mysqltuner.com/
>> Run with '--help' for additional options and output filtering
[OK] Logged in using credentials passed on the command line
-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.5.42
[OK] Operating on 64-bit architecture
-------- Storage Engine Statistics -------------------------------------------
[--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in MyISAM tables: 4M (Tables: 137)
[--] Data in InnoDB tables: 28M (Tables: 91)
[--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
[!!] Total fragmented tables: 91
-------- Security Recommendations -------------------------------------------
[!!] User 'root' has no password set.
[!!] User 'root' has no password set.
[!!] User 'root' has no password set.
[!!] User '' has no password set.
[!!] User '' has no password set.
-------- Performance Metrics -------------------------------------------------
[--] Up for: 2m 50s (728 q [4.282 qps], 130 conn, TX: 2M, RX: 106K)
[--] Reads / Writes: 92% / 8%
[--] Total buffers: 272.0M global + 4.2M per thread (151 max threads)
[OK] Maximum possible memory usage: 913.8M (23% of installed RAM)
[OK] Slow queries: 0% (0/728)
[OK] Highest usage of available connections: 3% (5/151)
[OK] Key buffer size / total MyISAM indexes: 64.0M/1.1M
[!!] Key buffer hit rate: 82.4% (85 cached / 15 reads)
[OK] Query cache efficiency: 44.2% (237 cached / 536 selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 43 sorts)
[!!] Joins performed without indexes: 1
[!!] Temporary tables created on disk: 41% (20 on disk / 48 total)
[OK] Thread cache hit rate: 96% (5 created / 130 connections)
[OK] Table cache hit rate: 90% (69 open / 76 opened)
[OK] Open file limit used: 0% (66/65K)
[OK] Table locks acquired immediately: 100% (366 immediate / 366 locks)
[OK] InnoDB data size / buffer pool: 28.0M/128.0M
-------- Recommendations -----------------------------------------------------
General recommendations:
Run OPTIMIZE TABLE to defragment tables for better performance
MySQL started within last 24 hours - recommendations may be inaccurate
Enable the slow query log to troubleshoot bad queries
Adjust your join queries to always utilize indexes
When making adjustments, make tmp_table_size/max_heap_table_size equal
Reduce your SELECT DISTINCT queries without LIMIT clauses
Variables to adjust:
join_buffer_size (> 1.0M, or always use indexes with joins)
tmp_table_size (> 32M)
max_heap_table_size (> 64M)