MB-8234: tune write ratio in DGM xperf config

Change-Id: I86ab2569a0bf1e0387720d7f95d38afdb1fc6b0a
Reviewed-on: http://review.couchbase.org/26463
Reviewed-by: Pavel Paulau <pavel.paulau@gmail.com>
Tested-by: Pavel Paulau <pavel.paulau@gmail.com>

conf/perf/xperf-mixed-bi-dgm.conf

@@ -1,6 +1,6 @@
 # XPERF test w/o views:
 # 16K ops/sec per cluster
-# 20% reads, 80% writes
+# 50% reads, 50% write (30% updates, 10% deletes, 10% inserts)
 # 16 clients per cluster
 # 20M dataset
 # bidirectional
@@ -25,7 +25,7 @@ hot_init_items=2000000
 wait_for_xdc_replication=1
 
 # access phase
-ratio_sets=0.8
+ratio_sets=0.5
 ratio_misses=0.0
 ratio_creates=0.20
 ratio_deletes=0.25