Obsolete:ariel

This page contains historical information. It may be outdated or unreliable.

ariel
Location:	pmtpa
Serial:	SM13360
Usage:	MYSQL
Status
Overall:	This device has been decommissioned.
Icinga?:	host status services status
Hardware
Memory:	7920 MBytes
CPU:	2 x AMD Opteron(tm) Processor 248
Software
OS:	Ubuntu 6.10
Kernel:	2.6.17

OBSOLETE: this server is no longer in service. (Oct 29 2010)

Ariel is the master DB server. Suda, the former master database server.

Note: As of 23 July 2005, samuel is the new master, and ariel is down.

Hardware

Motherboard: AccelerTech HDAMA AT02161 - http://www.accelertech.com/products/motherboard/ATO2161.php

Yes, it has BIOS console redirection.

Software

Some problems with kernel 2.6.7-rc3 on ariel. Some allocation_memory problems appear when stressing the machine. No more problems by disabling the swap.

Starting and stopping MySQL

• to start: sudo /usr/local/mysql/bin/mysqld_safe & (while logged in as a member of group wikidev). Normal response is Starting mysqld daemon with databases from /usr/local/mysql/var
• to stop: mysqladmin shutdown (use mysqladmin -uroot -p and supply the mysql root password if you don't have it in your my.cnf)

Process to switch to ariel

• In CommonSettings.php, set $wgReadOnlyFile

• Put read-only mysql on ariel
  • in mysql shell:

mysql: set global read_only = on

• Switch user and server to ariel in CommonSettings.php
  • $wgDBserver -> ariel (server)
  • same user as Suda
  • Disable linkscc, cause linkscc try to write. $wgEnablePersistentLC = false;

• Test wiki

• On suda, create an account for replicating the data.

mysql> GRANT REPLICATION SLAVE ON *.*
   -> TO 'repl'@'ariel-eth1' IDENTIFIED BY  'slavepass' ;

• To record the current log file name and offset, you should issue the following statements before you shutting down suda:

mysql> FLUSH TABLES WITH READ LOCK;
mysql> SHOW MASTER STATUS;

• shut down suda without unlocking the tables to make sure that the server goes down with the snapshot corresponding to the current log file and offset:

shell> mysqladmin -u root shutdown

• Copy the db to ariel
  • rsync -av /mnt/newdrive/newdata ariel:/usr/local/mysql/ --rsh=ssh --progress as root
  • Alternative: Use netcat (nc) instead. Unencrypted and therefor faster. 10 MByte/s have been observed between ariel and zwinger.

• Stop mysql on Ariel

• remove symlink /usr/local/mysql/data

• mv /usr/local/mysql/newdata to /usr/local/mysql/data

• restart mysql on ariel

• Test wiki

• Set the master/slave: On Suda, do:

mysql> CHANGE MASTER TO
   ->     MASTER_HOST='ariel-eth1',
   ->     MASTER_USER='repl',
   ->     MASTER_PASSWORD=' replication_password ',
   ->     MASTER_LOG_FILE=' recorded_log_file_name ',
   ->     MASTER_LOG_POS=recorded_log_position;

• Start the slave threads:

mysql> START SLAVE;

External links

• http://dev.mysql.com/doc/mysql/en/Replication_HOWTO.html