github.com/dctrud/umoci@v0.4.3-0.20191016193643-05a1d37de015/doc/site/quick-start/garbage-collection.md (about)

     1  +++
     2  title = "Garbage Collection"
     3  weight = 40
     4  +++
     5  
     6  Every umoci operation that modifies an image will not delete any now-unused
     7  blobs in the image (so as to ensure that any other operations that assume those
     8  blobs are present will not error out). However, this will result in a large
     9  number of useless blobs remaining in the image after operating on an image for
    10  a long enough period of time. `umoci gc` will garbage collect all blobs that
    11  are not reachable from any known image tag. Note that calling `umoci gc`
    12  between `umoci unpack` and `umoci repack` may result in errors if you've
    13  removed all references to the blobs used by `umoci unpack`.
    14  
    15  ```text
    16  % umoci gc --layout opensuse
    17  ```