不關機擴充 VM 的 GPT 磁碟格式空間

請搭配 https://xbddc.github.io/2018/12/21/expand-space-without-rebooting-vm/ 服用。

操作步驟

  1. 擴充 Raw Disk 磁碟大小
  2. 確認 Linux 已偵測到變更
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# dmesg | tail
[3362536.189973] virtio_blk virtio1: new size: 71720960 512-byte logical blocks (36.7 GB/34.2 GiB)
[3362536.189984] vda: detected capacity change from 19541262336 to 36721131520
[3362866.358221] EXT4-fs (vda1): resizing filesystem from 4742395 to 8936699 blocks
[3362866.389273] EXT4-fs (vda1): resized filesystem to 8936699
  1. 找到要 resize 的磁碟編號。注意只能是位於最末段的磁碟，如下的 vda1：
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# df
Filesystem     1K-blocks     Used Available Use% Mounted on
...
/dev/vda1       18318068 16648976   1652708  91% /
...
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# sgdisk -p /dev/vda
Disk /dev/vda: 38166527 sectors, 18.1 GiB
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): 877716F7-31D0-4D56-A1ED-4D566EFE418E
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 38166494
Partitions will be aligned on 2048-sector boundaries
Total free space is 2014 sectors (1007.0 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1          227328        38166494   18.0 GiB    8300
  14            2048           10239   4.0 MiB     EF02
  15           10240          227327   106.0 MiB   EF00
  1. 刪除並重新建立第 1 個分割區，並更新 partition table 取得新的設定資訊
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# sgdisk -d 1 /dev/vda 
# sgdisk -N 1 /dev/vda 
# partprobe /dev/vda
  1. 最後就執行 resize2fs 調整 ext2 大小：
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# resize2fs /dev/vda1
resize2fs 1.44.1 (24-Mar-2018)
Filesystem at /dev/vda1 is mounted on /; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 5
The filesystem on /dev/vda1 is now 8936699 (4k) blocks long.
  1. 確認一下結果，可以發現使用率從原本的 91% 降至 49%：
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# df
Filesystem     1K-blocks     Used Available Use% Mounted on
...
/dev/vda1       34578052 16649988  17911680  49% /
...

這樣就完成啦！

References