[linux-lvm] reduce size of snapshot - what is about previous reduce of file system ?

[Lentes, Bernd]

Hi,

i have a lv which has a snapshot. Size of the snapshot was too big while creating. So I'd like now to reduce the size of the snapshot for being able to create a second one. man lvreduce says: Shrinking snapshot logical volumes (...) is supported as well. Ok, that's fine. But normally, before shrinking a lv, the file system has to be reduced. But does the snapshot have a fs ? I never ran a mkfs.xxxx on it. Can I just reduce the size without doing anything before ? Or do I have to provide a -r to lvreduce ?

Thanks for any information.


Bernd

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Bernd Lentes

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[Brassow Jonathan]

Post by Lentes, Bernd
Hi,
i have a lv which has a snapshot. Size of the snapshot was too big while creating. So I'd like now to reduce the size of the snapshot for being able to create a second one. man lvreduce says: Shrinking snapshot logical volumes (...) is supported as well. Ok, that's fine. But normally, before shrinking a lv, the file system has to be reduced. But does the snapshot have a fs ? I never ran a mkfs.xxxx on it. Can I just reduce the size without doing anything before ? Or do I have to provide a -r to lvreduce ?
Thanks for any information.

The (non-thinly-provisioned) snapshot fills up from beginning to end. If it says it is 50% full, you should be able to reduce its size by roughly half. Be sure to leave a good margin of space for snapshots to use, as they will become invalid if they are overfilled.

brassow