[SOLVED] Metadata Sizing

[gsmitty]

Hello,

I have found a few threads that talk about how to resize metadata when resizing lvm thin volumes, but I'm having a difficult time finding documentation that gives guidelines for how large metadata should be compared to total storage size.

Is there an equation or ratio that I should be following to make sure my storage has the correct amount of metadata available? How much metadata, for example, would I need for media storage that occupies 4TB?

Thanks,

 

[bbgeek17]

This google search for "lvm thin metadata size" brings up this seemingly trustworthy source:
2MiB to approximately 15.88GiB

The article also refers to the "man" for "lvmthin":

 Size of pool metadata LV
       The amount of thin metadata depends on how many blocks are shared between thin LVs (i.e. through snapshots).  A thin pool with many snapshots may need a larger metadata LV.  Thin pool metadata LV sizes can be from  2MiB
       to approximately 16GiB.

       When using lvcreate to create what will become a thin metadata LV, the size is specified with the -L|--size option.

       When  an  LVM command automatically creates a thin metadata LV, the size is specified with the --poolmetadatasize option.  When this option is not given, LVM automatically chooses a size based on the data size and chunk
       size.

       It can be hard to predict the amount of metadata space that will be needed, so it is recommended to start with a size of 1GiB which should be enough for all practical purposes.  A thin pool metadata LV can later be man‐
       ually or automatically extended if needed.

       Configurable setting lvm.conf(5) allocation/thin_pool_crop_metadata gives control over cropping to 15.81GiB to stay backward compatible with older versions of lvm2. With enabled cropping there can be observed some prob‐
       lems when using volumes above this size with thin tools (i.e. thin_repair).  Cropping should be enabled only when compatibility is required.

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