optimize mysqldump for approx. 20GB databases for 8GB RAM MySQL server having following specifications:


8GB RAM 
Data &amp; Index of size 49.64GB
Dump file size is 17.24GB(18512936320 Bytes)
CPU:


Processor: Intel(R) Core(TM) i5-3330 CPU @ 3.00GHz
Architecture:   x86_64
vendor: Intel Corp.
size: 2400MHz
capacity: 2400MHz
width: 64 bits

OS:


Distributor ID:    Ubuntu
Description:   Ubuntu 14.04.5 LTS
Release:   14.04
Codename:  trusty



Free memory(RAM): this may be variable on specific time

         total       used       free     shared    buffers     cached


Mem:          7.7G       5.2G       2.5G        15M        44M       4.6G
-/+ buffers/cache:       597M       7.1G
Swap:         7.9G        61M       7.8G

Database 98% tables are InnoDB and rest of it are MyISAM.

I have used following query:

mysqldump -u root -p --single-transaction --routines --events --triggers --all-databases | gzip &gt; all_databases_backup.sql.gz


I have tried following Global variables :

key_buffer_size = 512M
Innodb_buffer_pool_size = 1024M
innodb_io_capacity = 2000
innodb_read_io_threads = 64
innodb_write_io_threads = 64
innodb_thread_concurrency = 0


To optimize the backup total time but not only able to reduce the time even 1 min.


With default settings it is taking min : 27mins
With the setting shown above it takes :  26mins


Is there any thing else I have to configure to optimize mysqldump?
I'm not sure about serious improvement of total time, but below some recommendations:


I suggest You - convert all tables into InnoDB format, and adjust memory for InnoDB:

Innodb_buffer_pool_size = 4096M


To main reasons - optimisation for single engine more easy to tune and MyISAM not affected by --single-transaction


Split dump and GZIP


I do not know, what part of table You have in MyISAM, but it always better - finish all works with database as fast as possible, than continue other steps

GZIP is may be exactly slowest part of Your script and it really not optimised. It use single core not depending how many of them You have.