SLAVE
If your Slaves are not Masters, then Slaves do not need binary logging at all. You can put a cap on the amount of relay log space accumulated by a Slave. In order to throttle relay logs at 4G, add relay_log_space_limit to /etc/my/.cnf on every Slave
[mysqld]
relay_log_space_limit=4G
and restart mysql
If you cannot set this, at least you should have some kind of alerting that does SHOW SLAVE STATUS\G and check the value of Relay_Log_Space (total bytes consumed by relay logs).
MASTER
As for the Master, you could set expire_logs_days to 1, but there is a severe warning I have for you...
If replication breaks, you have 1 day to fix it. Otherwise, a binary log on the Master may rotate away and you cannot run any CHANGE MASTER TO command to realign replication. I would leave expire_logs_days at 3 on the Master.
SUGGESTION #1
If you have any overnight bulk processing to do, maybe should run the bulk processes on on the Master with SET SQL_LOG_BIN=0; at the Start of the Session. This, of course, will not replicate to the Slave. You can perform the Same Bulk Load in Parallel to both Slaves.
SUGGESTION #2
Another thing you could do to manage the Master binary logs accumulation is this.
Run SHOW SLAVE STATUS\G on both Slaves. Look at Relay_Master_Log_File. That represents the binary log on the Master whose last command was executed on the Slave.
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 10.4.92.250
Master_User: replicant
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.009677
Read_Master_Log_Pos: 855227755
Relay_Log_File: relay-bin.000674
Relay_Log_Pos: 757296783
Relay_Master_Log_File: mysql-bin.009590
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 757296646
Relay_Log_Space: 94274010765
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 80561
1 row in set (0.00 sec)
In this example, Relay_Master_Log_File is mysql-bin.009590. All binary logs before this one can be removed from Master. You could run this on the Master:
PURGE BINARY LOGS TO 'mysql-bin.009590';
This will erase older logs and still leave replication in tact.
CAVEAT
Binary Logs are files that serially compiles (like a FIFO queue) all completed SQL transactions as either a SQL statement or a row change. A relay log is a file that collects binary log entries from a remote server (aka Master).
In MySQL Replication
- Master must have its binary logs enabled
- Slave compiles relay logs
- When all SQL in a relay log is processed, it is deleted
- On a Slave, when there is more that one relay log on a DB Server, it may indicate replication is falling behind because the IO thread is collecting SQL from a Master faster that the SQL thread can process the relay logs.
- Using relay_log_space_limit prevents replication from piling up and potentially filling up a disk. Relay logs rotate out based on rule #3
- It is possible for a DB Server to be both a Master and Slave. That's the only circumstance under which a Slave must have binary logs enabled. In that scenario, a DB Server will have both Binary Logs and Relay Logs.
If you failover to a Slave, and you want to Make it a Master
- service mysql stop
- Add
log-bin=mysql-bin to /etc/my.cnf on the Slave
- service mysql start
You will have to setup replication of other Slaves to the newly promoted Master and make sure the data on the Slave match up with the newly promoted Master
UPDATE 2012-08-13 17:47 EDT
According to the MySQL Documentation on relay-log option, you should define it. Here is why:
Due to the manner in which MySQL parses server options, if you specify this option, you must supply a value; the default basename is used only if the option is not actually specified. If you use the --relay-log option without specifying a value, unexpected behavior is likely to result; this behavior depends on the other options used, the order in which they are specified, and whether they are specified on the command line or in an option file. For more information about how MySQL handles server options, see Section 4.2.3, “Specifying Program Options”.
I did these steps :
set global slow_query_log=0;- remove the slow log file in system
set global slow_query_log=1;
it works fine, so I tried these steps:
mysql> set global slow_query_log=0;
Query OK, 0 rows affected (0.12 sec)
mysql> set global slow_query_log_file='/tmp/slow.log';
Query OK, 0 rows affected (0.10 sec)
mysql> set global slow_query_log=1;
Query OK, 0 rows affected (0.00 sec)
still works, and new slow log file is generated as /tmp/slow.log.
At last, the value of global variable log_output decides where to generate the general log and slow log's output, not the file format.
Best Answer
You should be able to set the binary logs to a new partition by providing the absolute path:
You might need to copy the old binary logs to the new directory and update the .index file with the new path information (Do this only when mysql is not running).
Why would you only want to binary log during certain intervals of the day? Doing this could really mess with your ability to restore at any given time.