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antlists wrote: |
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> On 23/11/2020 10:37, Michael wrote: |
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>>>> Have you changed the UUIDs on the new partitions? |
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> |
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>>> Never used UUID in fstab. Do I just run: blkid|grep UUID |
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>>> and copy it to fstab. |
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> |
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>> I warned you about UUIDs. The block device of /dev/sda* could be |
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>> pointing at |
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>> a partition either on the old, or the new disk. In such cases it is |
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>> a good |
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>> idea to find out what block devices the MoBo identifies and what the |
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>> kernel. |
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> |
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> If you're messing about with disks, partitions, etc, you NEED to have |
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> a basic understanding of UUIDs. Bear in mind that the UID bit (iirc) |
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> stands for *UNIQUE* ID. |
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> |
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> Linux (as has been said) allocates sda, sdb etc in the order it finds |
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> partitions, which can be somewhat random. So there is no guarantee, if |
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> you specify root as sda, something could glitch (or you've stuck an |
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> eSATA drive on, or or or) and suddenly it's sdb and your system can't |
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> find root! |
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> |
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> So what the initial boot system does is it sets up /dev/.../UUID as |
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> symlinks to the appropriate sdx. So when boot says "root = UUID", it |
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> looks at the symlink to find out whether it's sda, sdb, sdc or whatever. |
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> |
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> Now if you use dd to copy the old disk to the new, and leave both |
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> disks connected, anything looking by sda or sdb is going to find it |
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> but you won't know which disk it's found. At BEST the same applies to |
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> anything looking by UUID. But it could be a lot worse - anything that |
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> relies on the UUID being unique (which is what is promised) could do |
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> real damage to the system if they aren't. |
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> |
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> Read up on gdisk - I guess parted, fdisk, etc have the same - but it |
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> has the option to copy an MBR or GPT and generate new UUIDs for all |
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> the partitions. You MUST do that if you're leaving both drives in the |
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> system. |
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> |
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> Cheers, |
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> Wol |
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> |
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> |
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|
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|
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This is true. Even I switched to UUID wherever possible or labels. |
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Even external things I use UUID on when possible. I've been bit by this |
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once before and it was a hair pulling experience that I wouldn't want to |
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repeat or wish on one either. |
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|
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If UUID is something you don't want to spend time learning right now, |
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try using labels at least. Just make sure YOU use unique labels for |
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each one. Hint. home-old, home-new works pretty well at times. At |
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least you know it is home and which is old and which is new. Notes may |
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help too. ;-) |
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|
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Hope that helps. |
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|
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Dale |
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|
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:-) :-) |
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