mysql "flush logs" or "flush tables with read lock", ... hangs
 

Hi all,

This is a problem I am having for some time.

The policy is to backup mysql with mysql-zrm.
However at a certain stage it hangs forever.

THis is at the "flush logs".

I tried this manually and it gave the same result.
Even after restarting mysql and the host.

After some googling and trying I found out "flush tables with read lock" gives the same result.

The tables seem to be MyIsam.

I tried with a mysqldump on one server and restore it on a test vm.
I used the same config and flush logs still hangs.
ALso I tried to change some configuration directives... but with the same result

Help would be really appreciated!

Edit: btw, I checked the logfile and didn't found anything (/var/log/mysqld.log)
Edit2: I also did myisamchk -s *.MYI (in all direcoties with db files;actually did it with find command) and it did not return anything so datafiles seem ok.

Personally, I can't be more of help on this topic, just want to clear some things.
Do you have large amounts of data?
"it hangs": it loads CPU or just silently goes down and doesn't respond: not accepts connections, not replies with anything if accepts, etc? What is your MySQL server version?
Did you ever had same problem on other system(if you previously used that scheme)?

If I connect with the mysql client and type flush logs, it just takes forever to get back at the mysql prompt.
It just seems like this is doing nothing.
If I open a new terminal and connect again, this just works.

The database is 1.5 GB data in its whole(mysqldump).

I did a dump and imported it on another system and I got the same problem. Maybe a deadlock? I have no idea how to find this out.

tried that with a smaller amounts of data?
what were mysql server versions for both cases? did you try other version?

No. The customer is using RHEL and the default mysql server.
Dont know by heart what version it is. (but probably a pretty recent ones.)