In the last recipe, we created a pool, cache-pool
, based on SSDs. We will now use this pool as a cache tier for the erasure-coded pool, EC-pool
, that we created earlier in this chapter:
The following instructions will guide you through the creation of a cache tier with the writeback
mode and setting the overlay with an EC-pool
:
Create a cache tier that will associate storage-pools with cache-pools. The syntax is:
ceph osd tier add <storage_pool> <cache_pool>
:# ceph osd tier add EC-pool cache-pool
Set the cache mode as either
writeback
orread-only
. In this demonstration, we will usewriteback
, and the syntax is:ceph osd tier cachemode <cache_pool> writeback
:# ceph osd tier cache-mode cache-pool writeback
To direct all the client requests from the standard pool to the cache pool, set the pool overlay using the syntax:
ceph osd tier set-overlay <storage_pool> <cache_pool>
:# ceph osd tier set-overlay EC-pool cache-pool
On checking...