Nexus 3 Compact blob store task does not remove images physically

Question

We were deleting old docker images with keeping last 10 of them. We tried Compact blob store task to delete them physically but on the administration/Repository settings, Blob store still shows the same size after deleting images.

This is the compact blob store log:

2018-06-28 14:18:40,709+0200 INFO  [quartz-6-thread-20]  *SYSTEM org.sonatype.nexus.blobstore.compact.internal.CompactBlobStoreTask - Task information:
2018-06-28 14:18:40,712+0200 INFO  [quartz-6-thread-20]  *SYSTEM org.sonatype.nexus.blobstore.compact.internal.CompactBlobStoreTask -  ID: 2bf9a574-f3e6-4f8e-8351-d98e4abc5103
2018-06-28 14:18:40,712+0200 INFO  [quartz-6-thread-20]  *SYSTEM org.sonatype.nexus.blobstore.compact.internal.CompactBlobStoreTask -  Type: blobstore.compact
2018-06-28 14:18:40,712+0200 INFO  [quartz-6-thread-20]  *SYSTEM org.sonatype.nexus.blobstore.compact.internal.CompactBlobStoreTask -  Name: cbs
2018-06-28 14:18:40,712+0200 INFO  [quartz-6-thread-20]  *SYSTEM org.sonatype.nexus.blobstore.compact.internal.CompactBlobStoreTask -  Description: Compacting default blob store
2018-06-28 14:18:40,713+0200 INFO  [quartz-6-thread-20]  *SYSTEM org.sonatype.nexus.blobstore.file.FileBlobStore - Deletions index file rebuild not required
2018-06-28 14:18:40,713+0200 INFO  [quartz-6-thread-20]  *SYSTEM org.sonatype.nexus.blobstore.file.FileBlobStore - Begin deleted blobs processing
2018-06-28 14:18:41,551+0200 INFO  [quartz-6-thread-20]  *SYSTEM org.sonatype.nexus.blobstore.file.FileBlobStore - Elapsed time: 837.6 ms, processed: 45/45
2018-06-28 14:18:41,551+0200 INFO  [quartz-6-thread-20]  *SYSTEM org.sonatype.nexus.blobstore.compact.internal.CompactBlobStoreTask - Task complete

Answer 1

Docker layers can be shared across many different images, so the layers associated with an image are not deleted automatically when you delete an image. First run a "docker - delete unused manifests and images" task, then try running the compact blobstore again.