feat(conf): add journalWriteData config to bk conf (apache#12093)

Signed-off-by: Eric Shen <[email protected]>

conf/bookkeeper.conf

@@ -339,6 +339,14 @@ journalWriteBufferSizeKB=64
 # Should we remove pages from page cache after force write
 journalRemoveFromPageCache=true
 
+# Should the data be written on journal.
+# By default, data is written on journal for durability of writes.
+# Beware: while disabling data journaling in the Bookie journal might improve the bookie write performance, it will also
+# introduce the possibility of data loss. With no journal, the write operations are passed to the storage engine
+# and then acknowledged. In case of power failure, the affected bookie might lose the unflushed data. If the ledger
+# is replicated to multiple bookies, the chances of data loss are reduced though still present.
+journalWriteData=true
+
 # Should the data be fsynced on journal before acknowledgment.
 # By default, data sync is enabled to guarantee durability of writes.
 # Beware: while disabling data sync in the Bookie journal might improve the bookie write performance, it will also