ubuntu16.04 根分區(qū)設(shè)置太小，或是分區(qū)使用不合理，swap 分配過多，根目錄分配太少，導(dǎo)致整體的服務(wù)可用性和穩(wěn)定性較差，linux 2.6版本以后就可以實時擴容，下面內(nèi)容是通過parted 命令進行根分區(qū)擴容（將swap 分區(qū)刪除，并重新設(shè)置大小，并對根分區(qū)進行擴容操作）：
查看根分區(qū)所在磁盤
root # fdisk -l
Disk /dev/sda: 109.2 TiB, 120015311339520 bytes, 234404904960 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 262144 bytes / 262144 bytes
Disk /dev/sdb: 447.1 GiB, 480103981056 bytes, 937703088 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0x5ee33106
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 63487 61440 30M 83 Linux
/dev/sdb2 * 63488 195375103 195311616 93.1G 83 Linux
/dev/sdb3 195377150 937701375 742324226 354G 5 Extended
/dev/sdb5 195377152 937701375 742324224 354G 82 Linux swap / Solaris
parted 命令分區(qū)resized
parted 的命令，默認是按照盤符的順序進行操作，后不加參數(shù)，默認從/dev/sda 開始
步驟：
1. 先將swap 的分區(qū)刪除，回收空間
2. 用resizepart 對根分區(qū)進行擴容
3. 創(chuàng)建新的swap分區(qū)，并設(shè)置空間大小，注意設(shè)置大小的時候要帶上單位
root # parted /dev/sdb
GNU Parted 3.2
Using /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print all
Model: ATA Micron_5200_MTFD (scsi)
Disk /dev/sdb: 480GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 1049kB 32.5MB 31.5MB primary xfs
2 32.5MB 100GB 100GB primary ext4 boot
3 100GB 480GB 380GB extended
5 100GB 480GB 380GB logical linux-swap(v1)
Model: AVAGO MR9361-8i (scsi)
Disk /dev/sda: 120TB
Sector size (logical/physical): 512B/4096B
Partition Table: loop
Disk Flags:
Number Start End Size File system Flags
1 0.00B 120TB 120TB ext4
(parted) rm 5 # 刪除已有分區(qū)回收空間
(parted) rm 3
(parted) print
Model: ATA Micron_5200_MTFD (scsi)
Disk /dev/sdb: 480GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 1049kB 32.5MB 31.5MB primary xfs
2 32.5MB 100GB 100GB primary ext4 boot
(parted) resizepart 2
Warning: Partition /dev/sdb2 is being used. Are you sure you want to continue?
Yes/No? yes
End? [100GB]? 380G
(parted) print
Model: ATA Micron_5200_MTFD (scsi)
Disk /dev/sdb: 480GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 1049kB 32.5MB 31.5MB primary xfs
2 32.5MB 380GB 380GB primary ext4 boot
(parted) mkpart
Partition type? primary/extended? primary
File system type? [ext2]? linux-swap #設(shè)置文件系統(tǒng)類型
Start? 380 #需要增加單位此處為G
End? 480
Warning: You requested a partition from 380MB to 480MB (sectors 742187..937500).
The closest location we can manage is 380GB to 380GB (sectors 742187501..742187501).
Is this still acceptable to you?
Yes/No? No
(parted) mkpart #創(chuàng)建分區(qū)信息
Partition type? primary/extended? primary
File system type? [ext2]? linux-swap
Start? 380G
End? 480G
(parted)
(parted) P
Model: ATA Micron_5200_MTFD (scsi)
Disk /dev/sdb: 480GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 1049kB 32.5MB 31.5MB primary xfs
2 32.5MB 380GB 380GB primary ext4 boot
3 380GB 480GB 100GB primary linux-swap(v1) lba
(parted) p #查看分區(qū)信息
Model: ATA Micron_5200_MTFD (scsi)
Disk /dev/sdb: 480GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 1049kB 32.5MB 31.5MB primary xfs
2 32.5MB 380GB 380GB primary ext4 boot
3 380GB 480GB 100GB primary linux-swap(v1) lba
(parted) q
Information: You may need to update /etc/fstab.
resize2fs 更新文件系統(tǒng)中的磁盤大小
root# resize2fs /dev/sdb2
resize2fs 1.42.13 (17-May-2015)
Filesystem at /dev/sdb2 is mounted on /; on-line resizing required
old_desc_blocks = 12, new_desc_blocks = 45
The filesystem on /dev/sdb2 is now 92765501 (4k) blocks long.
修改/etc/fstab 更新新的swap 的uuid
// 生成swap 數(shù)據(jù)分區(qū)的UUID
root # mkswap /dev/sdb3
root # lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT
sda ext4 cdc2e9d4-8c36-480d-b4eb-bb8a3d436da9 /mnt/data
sdb
├─sdb1 xfs 6fa0130f-c478-41d1-a4da-1aeb8b6c0a60
├─sdb2 ext4 93958216-43dc-47b7-889c-03abbe9e3050 /
└─sdb3 swap 391c489b-47b5-4054-914e-58691a4ec16e
root # vim /etc/fstab
// 修改后保存即可
參考資料：
https://dade2.net/kb/how-to-resize-a-root-partition-in-ubuntu/
