MySQL my.ini file settings overwritten

Can you please specify exactly which properties in my.ini you have customized?
In Plesk Obsidian we have fixed this issue already, I just need to confirm that your redefined options are covered by the fix.
If this fix covers all your options, then we consider backport of this fix in Plesk Onyx with next MySQL update to avoid such problems for you in future.

After seeing this post. I went check my settings. It did the same thing to me. I'm on Windows 2016 version 17.8.11 Update #57. I'll have to look into the settings that were reverted. But most were related to the innodb settings. As well as the read buffer sizes and max connections and max user connections.

Yes, they were InnoDB settings for me too. max_connections is also important.

Lost settings for me are:

default-storage-engine=INNODB

read_buffer_size=1M

read_rnd_buffer_size=256K

sort_buffer_size=256K

join_buffer_size=1M

thread_cache_size=512

key_buffer_size=64M

innodb_flush_log_at_trx_commit = 2

innodb_log_buffer_size=1M

innodb_buffer_pool_size = 18G

innodb_log_file_size = 256M

innodb_thread_concurrency=0

innodb_io_capacity_max=2000

innodb_io_capacity=1500

innodb_buffer_pool_instances=8

innodb_purge_threads=1

innodb_file_per_table=1

innodb_read_io_threads=16

innodb_write_io_threads=16

innodb_ft_min_token_size = 3

innodb_ft_enable_stopword = OFF

innodb_ft_cache_size = 32M

max_connections = 512

I too faced this issue twice in past 2 months.

Is there any solution to avoid over written for my.ini file. in my case mysql data directly settings itself changed to default.

Quoted from Guest on Wednesday, 06 May 2026

Can you please specify exactly which properties in my.ini you have customized?
In Plesk Obsidian we have fixed this issue already, I just need to confirm that your redefined options are covered by the fix.
If this fix covers all your options, then we consider backport of this fix in Plesk Onyx with next MySQL update to avoid such problems for you in future.

Any updates here? Last week my.ini was overwritten again and caused a very udnesirable down time. Was the fix released?

Quoted from Guest on Wednesday, 06 May 2026

Any updates here? Last week my.ini was overwritten again and caused a very udnesirable down time. Was the fix released?

Same here. Also downtime thanks to the config reset (we normally run a HUGE innodb buffer, which was reset to a tiny one which was overwhelmed immediately).

Maybe someone @ Plesk would consider SOLVING this awful problem ?

The changelog states that it was indeed fixed in Plesk 17.8.11 MU70, can you please verify?

Hi. It seems that this "my.ini" file is no longer overwritten, for what I can see (On 12.5 and Onyx)

However, the very last question relates to Plesk Obsidian :
"In Which "MY.INI" file" do we need to set our parameters in Plesk Obsidian ?"

C:\Program Files (x86)\Plesk\Databases\MySQL\my.ini (File containing some parameters, and not stating it will be overwritten : it seems to be THE FILE to write into ...)
C:\Program Files (x86)\Plesk\Databases\MySQL\Data\my.ini (Very light file not containing a lot)
C:\Program Files (x86)\Plesk\MySQL\Data\my.ini (Very light file not containing a lot)
C:\Program Files (x86)\Plesk\MySQL\my.ini (Stated at the top of file that these changes will be overwritten)

Thanks for your help, for me, and for the community members coming to this page !

MySQL that serves customer databases uses %plesk_dir%\Databases\MySQL\my.ini and that's where custom settings should go. So indeed, in your case that would be C:\Program Files (x86)\Plesk\Databases\MySQL\my.ini.

The %plesk_dir%\MySQL\my.ini is used by a different instance of MySQL, for Plesk itself.