Objects with names starting with underscore become inaccessible after upgrading to Hammer
In Hammer, rgw objects whose names start with "_" and which were created with older versions of rgw (e.g. Giant) are inaccessible. They still appear in the bucket listing, but attempts to access them return NoSuchKey.
Objects with such names that are created with a Hammer rgw do not exhibit the problem.
#3 Updated by Yehuda Sadeh over 8 years ago
adding radosgw-admin command that fixes the bad objects that were created after hammer:
$ ./radosgw-admin bucket check --check-head-obj-locator \ --bucket=<bucket> [--fix]
also there's a --remove-bad flag that can be specified and can be used after the fix has been applied and tested.