我尝试将数据库移动到 Amazon EC2 实例上的 Ubuntu 安装上的其他挂载点，因为它已经填满了根目录。我想我搞砸了。当我运行：
$ sudo mysqld --datadir=/var/lib/mysql --user mysql
110412 11:36:44 [Warning] Can't create test file /mnt/var/lib/mysql/ip-10-244-207-161.lower-test
110412 11:36:44 [Warning] Can't create test file /mnt/var/lib/mysql/ip-10-244-207-161.lower-test
在/var/log/mysql/error.log：
110412 16:01:27 [Note] Plugin 'FEDERATED' is disabled.
/usr/sbin/mysqld: Can't find file: './mysql/plugin.frm' (errno: 13)
110412 16:01:27 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
/usr/sbin/mysqld: Can't create/write to file '/mnt/tmp/ibRTnZix' (Errcode: 13)
110412 16:01:27 InnoDB: Error: unable to create temporary file; errno: 13
110412 16:01:27 [ERROR] Plugin 'InnoDB' init function returned error.
110412 16:01:27 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
110412 16:01:27 [ERROR] /usr/sbin/mysqld: Can't create/write to file '/mnt/var/lib/mysql/ip-10-244-207-161.pid' (Errcode: 13)
110412 16:01:27 [ERROR] Can't start server: can't create PID file: Permission denied
该文件ip-10-244-207-161.lower-test尚不存在：
ls -l /mnt/var/lib/mysql
total 20532
-rwxr-xr-x 1 mysql root 0 2011-02-28 22:23 debian-5.1.flag
-rwxr-xr-x 1 mysql mysql 10485760 2011-04-12 07:31 ibdata1
-rwxr-xr-x 1 mysql mysql 5242880 2011-04-12 07:31 ib_logfile0
-rwxr-xr-x 1 mysql mysql 5242880 2011-02-28 22:23 ib_logfile1
drwxr-xr-x 2 mysql root 4096 2011-02-28 22:23 mysql
-rwxr-xr-x 1 mysql root 6 2011-02-28 22:23 mysql_upgrade_info
drwxr-xr-x 2 mysql mysql 4096 2011-04-11 08:22 scrapy_cache
该目录似乎可以访问：
$ ls -l /mnt/var/lib/ | grep mysql
drwxr-xr-x 4 mysql mysql 4096 2011-04-12 07:31 mysql
$ ls -l /var/lib/ | grep mysql
lrwxrwxrwx 1 mysql root 18 2011-04-12 09:05 mysql -> /mnt/var/lib/mysql
ls -ld /mnt/{,var/{,lib/{,mysql}}}
drwxr-xr-x 5 root root 4096 2011-04-12 07:27 /mnt/
drwxr-xr-x 3 mysql root 4096 2011-04-12 07:29 /mnt/var/
drwxr-xr-x 3 mysql ubuntu 4096 2011-04-12 07:33 /mnt/var/lib/
drwxr-xr-x 4 mysql mysql 4096 2011-04-12 07:31 /mnt/var/lib/mysql
我在my.cnf中更改的部分：
user = mysql
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /mnt/var/lib/mysql
tmpdir = /mnt/tmp
skip-external-locking
我真的很感激对此的一些帮助，因为我在尝试调试它时失败了。
我做了一个sudo chown -R mysql /mnt/var/lib/mysql所以一切都应该由mysql服务器拥有。在我迁移时/mnt运行，肯定是可写的。Mount证实了这一点：mv /var/lib/mysql /mnt/var/lib/
$ mount | grep /mnt
/dev/sda2 on /mnt type ext3 (rw)
磁盘空间未满，且没有用完 inode，磁盘配额似乎未处于活动状态我安装了repquota但它什么也没有输出：
$ df -h /dev/sda2
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 335G 2.0G 316G 1% /mnt
$ df -i /dev/sda2
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/sda2 44564480 104 44564376 1% /mnt
按照 MySQL 用户的工作方式创建事物，如评论中所建议的那样：
$ su -s /bin/bash - mysql
$ touch /mnt/var/lib/mysql/ip-10-244-207-161.lower-test
$ ls -ld /mnt/var/lib/mysql/ip-10-244-207-161.lower-test
-rw-r--r-- 1 mysql mysql 0 2011-04-12 14:10 /mnt/var/lib/mysql/ip-10-244-207-161.lower-test
$ rm -f /mnt/var/lib/mysql/ip-10-244-207-161.lower-test
$ ls -ld /mnt/var/lib/mysql/ip-10-244-207-161.lower-test
ls: cannot access /mnt/var/lib/mysql/ip-10-244-207-161.lower-test: No such file or directory
MySql 没有运行。
$ ps aux | grep mysql
ubuntu 20825 0.0 0.0 3700 776 pts/1 S+ 15:40 0:00 grep --color=auto mysql
/etc/mysql/my.cnf
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
# This will be passed to all mysql clients
# It has been reported that passwords should be enclosed with ticks/quotes
# escpecially if they contain "#" chars...
# Remember to edit /etc/mysql/debian.cnf when changing the socket location.
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
# Here is entries for some specific programs
# The following values assume you have at least 32M ram
# This was formally known as [safe_mysqld]. Both versions are currently parsed.
[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
#
# * Basic Settings
#
#
# * IMPORTANT
# If you make changes to these settings and your system uses apparmor, you may
# also need to also adjust /etc/apparmor.d/usr.sbin.mysqld.
#
user = mysql
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /mnt/var/lib/mysql
tmpdir = /mnt/tmp
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address = 127.0.0.1
#
# * Fine Tuning
#
key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover = BACKUP
#max_connections = 100
#table_cache = 64
#thread_concurrency = 10
#
# * Query Cache Configuration
#
query_cache_limit = 1M
query_cache_size = 16M
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
#general_log_file = /var/log/mysql/mysql.log
#general_log = 1
log_error = /var/log/mysql/error.log
# Here you can see queries with especially long duration
#log_slow_queries = /var/log/mysql/mysql-slow.log
#long_query_time = 2
#log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
# other settings you may need to change.
#server-id = 1
#log_bin = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size = 100M
#binlog_do_db = include_database_name
#binlog_ignore_db = include_database_name
#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!
#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
#no-auto-rehash # faster start of mysql but no tab completition
[isamchk]
key_buffer = 16M
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
答案1
答案2
该文件是否/mnt/var/lib/mysql/ip-10-244-207-161.lower-test存在？如果是，它的所有者是 吗mysql？ 目录中的所有文件/mnt/var/lib/mysql都应归 MySQL 用户所有。
是否/mnt已安装为rw(读写)，而不是ro(只读)？您可以通过运行mount(不带参数) 来检查。
MySQL 有一个其文档中的页面关于此错误。这基本上意味着数据目录或文件系统受到写保护。
磁盘配额是否处于活动状态？您可以使用以下命令检查当前配额状态（如果已安装）：
sudo repquote -a
磁盘已满吗？使用以下命令检查当前磁盘使用情况：
df -h
答案3
问题似乎是由于 的父目录权限不足造成的/mnt/var/lib/mysql，可能/mnt/var具体是 。你能发布 的输出ls -ld /mnt/{,var/{,lib/{,mysql}}}吗？
编辑：好的，我再考虑一下。你说你改变了套接字的位置my.cnf——可能是服务器是成功启动（使用 检查ps ax | grep mysql）但 mysql客户您使用的是否正在其他地方（例如旧位置）寻找套接字？运行后收到的完整错误消息是什么mysql？
答案4
您是否输入了错误的数据目录？
你写了：
$ sudo mysqld --datadir=/var/lib/mysql --user mysql
但应该是：
$ sudo mysqld --datadir=/mnt/var/lib/mysql --user mysql