Our MySQL 5.0.51a running on Debian Lenny is going slow a few minutes after start. There is no sign of taking a lot of resources, "top" says less than 10% cpu and less than 10% MEM.
As for now the mysqld is restarted every 7 minutes...

During startup syslog says
"InnoDB: HugeTLB: Warning: Failed to allocate 8404992 bytes. errno 12"

php-cgi segfaults just after restart and
"WordPress database error MySQL server has gone away for query" as expected(?) (there is no db for a few seconds)

The database is 700 Mb, 3300 tables and running Wordpress. mysql and php runs of different machines.


Please help!

Well, there's not alot we can help you with, since there's not enough details. How much memory is on the machine? CPU? 3300 tables is a bit high, but how many transactions/users are running through this DB?

And did you try to look up the error you're getting????
http://forums.mysql.com/read.php?24,196455,196476

You're going to have to modify things to use huge pages.

There are 2 cpus with 2 cores each and 8 Gb memory.
I do not know the exact number of transactions/users, but max ~ 30 pageview / minute.
The server should have no problem with this.

Cpu(s): 0.8%us, 0.2%sy, 0.0%ni, 98.8%id, 0.0%wa, 0.0%hi, 0.2%si, 0.0%st
Mem: 9169304k total, 5824604k used, 3344700k free, 50844k buffers
Swap: 2650684k total, 0k used, 2650684k free, 856628k cached



Yes I have read that thread and followed the guide here:
http://www.cyberciti.biz/tips/linux-...rformance.html

cat /proc/meminfo | grep Huge
HugePages_Total: 40
HugePages_Free: 40
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB

Looks like mySQL is not using any of it (HugePages_Free: 40)

Well, if it's not using it, then there's obviously some part of the configuration that was missed. The link to the MySQL forums page had troubleshooting info on it, since it dealt with that topic specifically.

It seems like I placed "ulimit -l unlimited" at the wrong place.
It is now in the mysql initscript

Almost, there
"InnoDB: HugeTLB: Warning: Failed to allocate 8404992 bytes. errno 12" is gone but
"Warning: Failed to allocate 952107008 bytes from HugeTLB memory. errno 12"

So it can allocate 8 404 992 bytes but not 952 107 008

It turns out that
HugePages_Total: 40
Hugepagesize: 2048 kB

40 * 2048 k > 8404992
but
40 * 2048 k < 952107008

So to summarize, for those with the same problem:
Follow the guide here
http://www.cyberciti.biz/tips/linux-...rformance.html
change
vm.nr_hugepages= X
where X should be more than
Failed to allocate 952107008 bytes / Hugepagesize / 1000
and X * 2048 k should be less than your mem.

Add
ulimit -l unlimited
to mysql initscript
run sysctl -p

restart mysql