[mythtv-users] Poor performance with ZFS (ZFS on Linux)

[Rajil Saraswat]

I initially started out with fully populated mythconverg db
(MythVideo/Pictures/Recordings..) and it took ~15 minutes to run
mythfilldatabase on ZFS, whereas the same query was done in ~20seconds
on ext4. Following that i started testing out with a fresh install of
mythconverg without any recordings and a single tuner. I am using the
'my-large.cnf' file from mariadb as a basis which has the comment at the
beginning, ' This is for a large system with memory of 1G-2G where the
system runs mainly MariaDB'. I have added the following lines to
my-large.cnf,


innodb_data_home_dir            = /var/lib/mysql/innodb                   
innodb_log_group_home_dir       = /var/lib/mysql/logs                     
innodb_doublewrite = 0                                                    
skip-name-resolve                                                    
innodb_use_native_aio=0                                                   
expire_logs_days = 10                                                     
max_binlog_size  = 100M                                                
bind-address=0.0.0.0 

'time mysqldump -h 172.16.1.195 -u mythtv mythconverg -p > /dev/null'
takes about 4 seconds for me including the time to type in the password.

The system has a Xeon E3-1275 v6 CPU and has 12GB of RAM at present
(will bump it to 16GB when put into production). I have two pools one
for the boot drive (holds grub) and second for the OS. Both of them sit
on the same mirrored SSD. The normal recommendation for ZFS is to have 1
GB of RAM per TB of disk space. My SSD size is only 300GB and fulfills
that criterion.

I am wondering whether i should partition these disks further to get a
separate 1GB ext4 partition to hold /var/lib/mysql.

Thanks