Testing a cache tier

Since our cache tier is ready, during the write operation, clients will see what is being written to their regular pools, but actually, it's being written on cache-pools first and then, based on the cache tier policy data, it will be flushed to the storage tier. This data migration is transparent to the client.

How to do it...

1. In the previous recipe, we created a 500 MB test file named /tmp/file1; we will now put this file in an EC-pool:

        # rados -p EC-pool put object1 /tmp/file1

2. Since an EC-pool is tiered with a cache-pool, the named file1 will get written to the EC-pool as object metadata, but the actual object will get written into the cache-pool. To verify this, list each pool to get the object names:

        # rados -p EC-pool ls
        # rados -p cache-pool ls

This is shown in the following screenshot:

3. When viewing rados df, we can see the actual space the object is taking up in each of the pools and where it truly resides:

        # rados df

This is shown in the...