[mythtv-users] Performance MySQL on RAM

[Warpme]

On 10/22/12 10:59 PM, Josu Lazkano wrote:
> Hello,
>
> I have some questions abot MySQL performance, I have a dedicatd server
> for the backend with 2GB of memory. I am thinking on buy 2GB more and
> get 4GB of RAM.
>
> Is possible to use RAM memory to optimize MySQL?
>
> I add 2 lines on the configuration:
>
> tmp_table_size          = 256M
> max_heap_table_size     = 256M
>
> This is my complete MySQL configuration:
>
> [client]
> port		= 3306
> socket		= /var/run/mysqld/mysqld.sock
>
> [mysqld_safe]
> socket		= /var/run/mysqld/mysqld.sock
> nice		= 0
>
> [mysqld]
> tmp_table_size          = 256M
> max_heap_table_size     = 256M
>
> user		= mysql
> pid-file	= /var/run/mysqld/mysqld.pid
> socket		= /var/run/mysqld/mysqld.sock
> port		= 3306
> basedir		= /usr
> datadir		= /var/lib/mysql
> tmpdir		= /tmp
> lc-messages-dir	= /usr/share/mysql
> skip-external-locking
> key_buffer		= 16M
> max_allowed_packet	= 16M
> thread_stack		= 192K
> thread_cache_size       = 8
> myisam-recover         = BACKUP
> query_cache_limit	= 1M
> query_cache_size        = 16M
> expire_logs_days	= 10
> max_binlog_size         = 100M
>
> [mysqldump]
> quick
> quote-names
> max_allowed_packet	= 16M
>
> [mysql]
>
> [isamchk]
> key_buffer		= 16M
>
> !includedir /etc/mysql/conf.d/
>
> How could I check the performance of the database?
>
> Thanks and best regards.
>
Hi,

Recently I switch DB from HDD (2TB GreenCaviar with /temp on tempfs) to 
RAMdisk + sync daemon.
Difference:
-scheduling speed up about 10%
-playback starts approx 1,5-2x faster (1-2sec->0,5-1sec)
-mythweb feels faster, difference is roughly about 1sec->0,5sec (guide 
with 50+ channels)

Summarizing:
Incremental QoE isn't worth negative side effects of RAMdisk (potential 
losses of data or extra costs to avoid them)

I think almost comparable speed-up can be achieved with tuning mysql + 
installing RAM in system as Linux does perfect job in using free RAM as 
disk buffers...
I already have tuned mysql but in free time I will try to experiment 
little with increasing mysql caches

-br



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