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不重启的情况下重读分区
partprobe 命令 用于重读分区表，当出现删除文件后，出现仍然占用空间。可以 partprobe 在不重启的情况下重读分区。
| -d：不更新内核； |
| -s：显示摘要和分区； |
| -h：显示帮助信息； |
| -v：显示版本信息。 |
设备：指定需要确认分区表改变的硬盘对应的设备文件。
使用 partprobe 不重启系统添加新的磁盘分区，主机自带硬盘超过 300GB，目前只划分使用了 3 个主分区，不到 70GB，如下：
| [root@localhost ~]# df -h |
| Filesystem Size Used Avail Use% Mounted on |
| /dev/sda1 29G 3.7G 24G 14% / |
| /dev/sda2 29G 22G 5.2G 81% /oracle |
| tmpfs 2.0G 0 2.0G 0% /dev/shm |
| [root@localhost ~]# cat /proc/partitions |
| major minor #blocks name |
| |
| 8 0 311427072 sda |
| 8 1 30716248 sda1 |
| 8 2 30716280 sda2 |
| 8 3 8193150 sda3 |
| 8 16 976896 sdb |
| 8 32 976896 sdc |
| |
| …省略其他 |
现在需要给系统添加 1 个 100GB 的空间存放数据文件，而又不影响现有系统上业务的运行，使用 fdisk 结合 partprobe 命令不重启系统添加一块新的磁盘分区。操作步骤如下：
第 1 步 添加新的磁盘分区 ：
| [root@localhost ~]# fdisk /dev/sda |
| The number of cylinders for this disk is set to 38770. |
| There is nothing wrong with that, but this is larger than 1024, |
| and could in certain setups cause problems with: |
| 1) software that runs at boot time (e.g., old versions of lilo) |
| 2) booting and partitioning software from other OSs |
| (e.g., DOS FDISK, OS/2 FDISK) |
| |
| command (m for help): p |
| |
| Disk /dev/sda: 318.9 GB, 318901321728 bytes |
| 255 heads, 63 sectors/track, 38770 cylinders |
| Units = cylinders of 16065 * 512 = 8225280 bytes |
| |
| Device Boot Start End Blocks id System |
| /dev/sda1 * 1 3824 30716248+ 83 Linux |
| /dev/sda2 3825 7648 30716280 83 Linux |
| /dev/sda3 7649 8668 8193150 82 Linux swap / Solaris |
| |
| Command (m for help): n |
| Command action |
| e extended |
| p primary partition (1-4) |
| p |
| Selected partition 4 |
| First cylinder (8669-38770, default 8669): |
| Using default value 8669 |
| last cylinder or +size or +sizeM or +sizeK (8669-38770, default 38770): +100G |
| Command (m for help): w |
| The partition table has been altered! |
| |
| Calling ioctl() to re-read partition table. |
| |
| WARNING: Re-reading the partition table failed with error 16: |
| |
| Device or resource busy. |
| The kernel still uses the old table. |
| The new table will be used at the next reboot. |
| Syncing disks. |
第 2 步 使用工具 partprobe 让 kernel 读取分区信息：
| [root@localhost ~]# partprobe |
使用 fdisk 工具只是将分区信息写到磁盘，如果需要 mkfs 磁盘分区则需要重启系统，而使用 partprobe 则可以使 kernel 重新读取分区信息，从而避免重启系统。
第 3 步 格式化文件系统：
| [root@localhost ~]# mkfs.ext3 /dev/sda4 |
| mke2fs 1.39 (29-May-2006) |
| Filesystem label= |
| OS type: Linux |
| Block size=4096 (log=2) |
| Fragment size=4096 (log=2) |
| 12222464 inodes, 24416791 blocks |
| 1220839 blocks (5.00%) reserved for the super user |
| First data block=0 |
| Maximum filesystem blocks=4294967296 |
| 746 block groups |
| 32768 blocks per group, 32768 fragments per group |
| 16384 inodes per group |
| Superblock backups stored on blocks: |
| 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, |
| 2654208, 4096000, 7962624, 11239424, 20480000, 23887872 |
| |
| Writing inode tables: done |
| Creating journal (32768 blocks): done |
| Writing superblocks and filesystem accounting information: |
| |
| done |
| |
| This filesystem will be automatically checked every 26 mounts or |
| 180 days, whichever comes first. Use tune2fs -c or -i to override. |
| [root@localhost ~]# |
第 4 步 mount 新的分区 /dev/sda4：
| [root@localhost ~]# e2label /dev/sda4 /data |
| [root@localhost ~]# mkdir /data |
| [root@localhost ~]# mount /dev/sda4 /data |
| [root@localhost ~]# df |
| Filesystem 1K-blocks Used Available Use% Mounted on |
| /dev/sda1 29753556 3810844 24406900 14% / |
| /dev/sda2 29753588 11304616 16913160 41% /oracle |
| tmpfs 2023936 0 2023936 0% /dev/shm |
| /dev/sda4 96132968 192312 91057300 1% /data |
使用 partprobe 可以不用重启系统即可配合 fdisk 工具创建新的分区。
