20250819 59.125.229.6 df for Raid

[root@dns /]# df
Filesystem     1K-blocks     Used Available Use% Mounted on
devtmpfs        16337000        0  16337000   0% /dev
tmpfs           16345596        0  16345596   0% /dev/shm
tmpfs           16345596    18316  16327280   1% /run
tmpfs           16345596        0  16345596   0% /sys/fs/cgroup
/dev/md126      58597408 17956856  40640552  31% /
/dev/md127       1942528   285280   1657248  15% /boot
/dev/md122      19527680  8505256  11022424  44% /cnroot
/dev/md120      39075168  5169340  33905828  14% /var
/dev/md124      19527680 12710568   6817112  66% /cyroot
/dev/md119     156300704 27218488 129082216  18% /home
/dev/loop1         52224    52224         0 100% /var/lib/snapd/snap/snapd/24718
/dev/loop2         68480    68480         0 100% /var/lib/snapd/snap/core24/1055
/dev/loop0         56320    56320         0 100% /var/lib/snapd/snap/certbot/4737
/dev/loop4         65408    65408         0 100% /var/lib/snapd/snap/core20/2582
/dev/loop5         56320    56320         0 100% /var/lib/snapd/snap/certbot/4892
/dev/loop3         68480    68480         0 100% /var/lib/snapd/snap/core24/1006
/dev/loop6         50560    50560         0 100% /var/lib/snapd/snap/snapd/24792
/dev/md125      19568640  9633504   9935136  50% /var/lib/mysql
/dev/loop7         65408    65408         0 100% /var/lib/snapd/snap/core20/2599
/dev/md117      39075168 19282576  19792592  50% /var/www
tmpfs            3269120        0   3269120   0% /run/user/0
/dev/md118      39075168    33568  39041600   1% /var/lib/mysql1

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In CentOS, the UUID (Universally Unique Identifier) of a RAID array is used to reliably identify and mount the array, regardless of the device names assigned by the system. This is particularly useful for software RAID configurations managed by mdadm. To find the UUID of a RAID array, you can use the blkid command or examine the RAID superblock information. 

Finding the UUID of a RAID array:

  1. 1. Using blkid:

    • The blkid command lists information about all block devices, including UUIDs. 
    • To find the UUID of a specific RAID array, you need to identify the device name (e.g., /dev/md0, /dev/md1) and then use blkid on that device. 
    • Example: sudo blkid /dev/md0 

  2. 修改 fstab 的注意事項:

  3. 修改 fstab 需要root權限。 
  4. 在修改 fstab 之前，最好備份原始文件，以防出錯。 
  5. 確保所有條目都正確無誤，包括設備、掛載點和文件系統類型，否則可能導致系統啟動問題。 
  6. 可以使用 mount -a 命令在不重啟系統的情況下掛載 fstab 中定義的所有文件系統，以便測試修改是否正確。 
  7. 如果 fstab 設置錯誤，可能導致系統無法啟動，需要進入單用戶模式進行修復，Google Cloud。