我们准备备份或维护数据的时候，常常会考虑磁盘空间大小的问题，通常需要知道我们的数据和日志有多大。数据是至关重要的，数据是生命线。
使用mysqldiskusage 工具来查看数据库实例使用到的空间，包括数据库和各种日志大小。
实例
shell> sudo env PYTHONPATH=$PYTHONPATH mysqldiskusage \
--server=root:root@localhost --all
# Source on localhost: ... connected.
# Database totals:
+-----------------+--------------+
| db_name | total |
+-----------------+--------------+
| oltp2 | 829,669 |
| bvm | 15,129 |
| db1 | 9,895 |
| db2 | 11,035 |
| employees | 206,117,692 |
| griots | 14,415 |
| mysql | 995,722 |
| oltp1 | 177,393 |
| room_temp | 9,847 |
| sakila | 791,727 |
| test | 647,911 |
| test_arduino | 9,999 |
| welford_kindle | 72,032 |
| world | 472,785 |
| world_innodb | 829,669 |
+-----------------+--------------+
Total database disk usage = 210,175,251 bytes or 200.44 MB
# Log information.
+--------------------+--------------+
| log_name | size |
+--------------------+--------------+
| host123.log | 957,282,265 |
| host123-slow.log | 123,647 |
| host123.local.err | 321,772,803 |
+--------------------+--------------+
Total size of logs = 1,279,178,715 bytes or 1.19 GB
# Binary log information:
Current binary log file = my_log.000287
+----------------+---------+
| log_file | size |
+----------------+---------+
| my_log.000285 | 252208 |
| my_log.000286 | 256 |
| my_log.000287 | 3063 |
| my_log.index | 48 |
+----------------+---------+
Total size of binary logs = 255,575 bytes or 249.58 KB
# Server is not an active slave - no relay log information.
# InnoDB tablespace information:
+--------------+--------------+
| innodb_file | size |
+--------------+--------------+
| ib_logfile0 | 5,242,880 |
| ib_logfile1 | 5,242,880 |
| ibdata1 | 815,792,128 |
| ibdata2 | 52,428,800 |
+--------------+--------------+
Total size of InnoDB files = 889,192,448 bytes or 848.00 MB
InnoDB freespace = 635,437,056 bytes or 606.00 MB
使用–all选项，将显示所有日志和InnoDB的磁盘使用情况。也会列出所有数据库，即使不包含任何数据。
权限
用户必须具有读取数据目录的权限。