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From benoit lair <>
Subject CS 4 Database integrity - mysql server performances
Date Thu, 14 Feb 2013 10:24:25 GMT

I'm testing a cs 4 preproduction testing environment. I was asking me what
if mysql server go away or mysql server was not enough big for the cs mgmt
server requirements.

My mysql server has 2 Gb of ram, i ran the and saw these
results :

[root@cloudstack-master-server ~]# ./

 >>  MySQLTuner 1.2.0 - Major Hayden <>
 >>  Bug reports, feature requests, and downloads at
 >>  Run with '--help' for additional options and output filtering
Please enter your MySQL administrative login: root
Please enter your MySQL administrative password:

-------- General Statistics
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.1.61-log
[OK] Operating on 64-bit architecture

-------- Storage Engine Statistics
[--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in InnoDB tables: 34M (Tables: 166)
[--] Data in MEMORY tables: 125K (Tables: 2)
[!!] Total fragmented tables: 166

-------- Security Recommendations
[OK] All database users have passwords assigned

-------- Performance Metrics
[--] Up for: 55d 23h 4m 47s (175M q [36.356 qps], 120 conn, TX: 37B, RX:
[--] Reads / Writes: 90% / 10%
[--] Total buffers: 98.0M global + 18.6M per thread (350 max threads)
[!!] Maximum possible memory usage: 6.5G (353% of installed RAM)
[OK] Slow queries: 0% (0/175M)
[OK] Highest usage of available connections: 4% (15/350)
[OK] Key buffer size / total MyISAM indexes: 8.0M/92.0K
[OK] Key buffer hit rate: 99.6% (1K cached / 4 reads)
[OK] Query cache efficiency: 28.1% (14M cached / 52M selects)
[!!] Query cache prunes per day: 21931
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 3M sorts)
[!!] Joins performed without indexes: 54279
[OK] Temporary tables created on disk: 0% (299 on disk / 3M total)
[OK] Thread cache hit rate: 70% (35 created / 120 connections)
[!!] Table cache hit rate: 1% (64 open / 3K opened)
[OK] Open file limit used: 0% (6/1K)
[OK] Table locks acquired immediately: 100% (17M immediate / 17M locks)
[OK] InnoDB data size / buffer pool: 34.1M/40.0M

-------- Recommendations
General recommendations:
    Run OPTIMIZE TABLE to defragment tables for better performance
    Reduce your overall MySQL memory footprint for system stability
    Enable the slow query log to troubleshoot bad queries
    Adjust your join queries to always utilize indexes
    Increase table_cache gradually to avoid file descriptor limits
Variables to adjust:
  *** MySQL's maximum memory usage is dangerously high ***
  *** Add RAM before increasing MySQL buffer variables ***
    query_cache_size (> 32M)
    join_buffer_size (> 16.0M, or always use indexes with joins)
    table_cache (> 64)

Okay, i know i configured very too strongly certains buffers so theorically
i can override the physical capacity of this server.

But what about the query cache prunes per day ?
Other question, if i have connections aborted, is it dangerous for the cs
db integrity ?
Also if i reach the max connections ? Is ti dangerous too

What are the cases i must absolutely avoid in order to keep my cs db
integrity ?

Thanks for your answers.

Regards, Benoit Lair.

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