DAOS-14781 test: expect more containers before rdb nospace (#13647) (#…

…13658)

Change the server/metdata.py tests to expect, for a pool rdb capacity
of 128 MiB, out of space errors just before creating a maxiimum of
about 7500 containers (increasing from the prior value 3000).

To avoid out of space errors on pool service replica followers,
in the server/metadata.yaml functional test config, change the
rdb log compaction frequency (RDB_COMPACT_THRESHOLD) to be once every
64 entries, rather than the prdoduct default 256. For applications
that push the metadata/rdb space to its limits, this is one tactic to
reduce the amount of free space skew between the leader and followers.
Such skew, if allowed to become too large, can cause followers to run
out of space in rdb before the next periodic trigger of log compaction.
And that of course can impact overall pool service availability.

Signed-off-by: Kenneth Cain <[email protected]>

src/tests/ftest/server/metadata.py

@@ -65,7 +65,7 @@ class ObjectMetadata(TestWithServers):
     CREATED_CONTAINERS_MIN = 2900
 
     # Number of created containers that should not be possible
-    CREATED_CONTAINERS_LIMIT = 3500
+    CREATED_CONTAINERS_LIMIT = 7500
 
     def __init__(self, *args, **kwargs):
         """Initialize a TestWithServers object."""

src/tests/ftest/server/metadata.yaml

@@ -21,6 +21,7 @@ server_config:
       log_mask: DEBUG,MEM=ERR
       env_vars:
         - DAOS_MD_CAP=128
+        - RDB_COMPACT_THRESHOLD=64
         - DD_MASK=group_metadata_only
       storage:
         0:
@@ -38,6 +39,7 @@ server_config:
       log_mask: DEBUG,MEM=ERR
       env_vars:
         - DAOS_MD_CAP=128
+        - RDB_COMPACT_THRESHOLD=64
         - DD_MASK=group_metadata_only
       storage:
         0:
@@ -47,7 +49,6 @@ server_config:
 pool:
   svcn: 5
   scm_size: 1G
-  nvme_size: 8G
   control_method: dmg
 container:
   control_method: API