在MySQL数据库的维护过程中，我们有时候会在MySQL的错误日志文件中看到一些关于Operating system error的错误信息，例如在MySQL的错误日志里面，有时候会看到关于
InnoDB: Operating system error number 0.
InnoDB: Check that your OS and file system support files of this size.
InnoDB: Check also that the disk is not full or a disk quota exceeded.
InnoDB: Operating system error number 5.
...........................................
那么这些System Error Code在Linux下分别代表什么意思呢？其实如果遇到错误日志里有这些对应的代码，使用MySQL自带的命令工具perror查看一下具体信息即可。非常简单方便。
[root@DB-Server ~]# perror 2;
OS error code 2: No such file or directory
[root@DB-Server ~]# perror 3;
OS error code 3: No such process
[root@DB-Server ~]# perror 4;
OS error code 4: Interrupted system call
[root@DB-Server ~]# perror 5;
OS error code 5: Input/output error
[root@DB-Server ~]#
如果你要查看一个范围的Operating system error，可以使用下面命令
[root@DB-Server ~]# perror `seq 0 10`
OS error code 0: Success
OS error code 1: Operation not permitted
OS error code 2: No such file or directory
OS error code 3: No such process
OS error code 4: Interrupted system call
OS error code 5: Input/output error
OS error code 6: No such device or address
OS error code 7: Argument list too long
OS error code 8: Exec format error
OS error code 9: Bad file descriptor
OS error code 10: No child processes
[root@DB-Server ~]#
如果是集群，那么可以shell> perror --ndb errorcode查看， 下面表格是关于Linux平台下通用的System Error Code列表，如下所示，完全没有必要硬性记住。遇到查看即可。
| Number | Macro | Description |
| 1 | EPERM | Operation not permitted |
| 2 | ENOENT | No such file or directory |
| 3 | ESRCH | No such process |
| 4 | EINTR | Interrupted system call |
| 5 | EIO | I/O error |
| 6 | ENXIO | No such device or address |
| 7 | E2BIG | Arg list too long |
| 8 | ENOEXEC | Exec format error |
| 9 | EBADF | Bad file number |
| 10 | ECHILD | No child processes |
| 11 | EAGAIN | Try again |
| 12 | ENOMEM | Out of memory |
| 13 | EACCES | Permission denied |
| 14 | EFAULT | Bad address |
| 15 | ENOTBLK | Block device required |
| 16 | EBUSY | Device or resource busy |
| 17 | EEXIST | File exists |
| 18 | EXDEV | Cross-device link |
| 19 | ENODEV | No such device |
| 20 | ENOTDIR | Not a directory |
| 21 | EISDIR | Is a directory |
| 22 | EINVAL | Invalid argument |
| 23 | ENFILE | File table overflow |
| 24 | EMFILE | Too many open files |
| 25 | ENOTTY | Inappropriate ioctl for device |
| 26 | ETXTBSY | Text file busy |
| 27 | EFBIG | File too large |
| 28 | ENOSPC | No space left on device |
| 29 | ESPIPE | Illegal seek |
| 30 | EROFS | Read-only file system |
| 31 | EMLINK | Too many links |
如果是Windows平台，那么也可以使用下面命令查看具体的System Error Code信息，另外，Windows平台下的System Error Code也远比Linux平台下要多，遇到了这些System Error Code，使用命令查看即可。
perror.exe 2
perror `perl -e "print join ' ',1..100"`
参考资料：
http://doc.docs.sk/mysql-refman-5.5/operating-system-error-codes.html