wenbingshen commented on code in PR #4258:
URL: https://github.com/apache/bookkeeper/pull/4258#discussion_r1582074412


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site3/website/src/pages/bps/BP-66-support-throttling-for-zookeeper-read-of-rereplication.md:
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+# BP-66: support throttling for zookeeper read of rereplication
+
+### Motivation
+
+Each time the cluster trigger the re-replication, all replicators will read 
data from zookeeper. This can cause a great pressure on Zookeeper. We need to 
support throttling for zookeeper read of re-replication.
+
+For example, in a Pulsar cluster, we enable auto-recovery for every bookie. 
There are 400 bookies in a cluster, which means there are 400 replicators in 
the cluster.
+And there are about 3000 ledgers in each bookie, 1/3 of them are small 
ledgers, whose size is less than 0.1MB, that is 1000 small ledgers in each 
bookie.
+If we decommission one bookie, the read latency of zookeeper will increase to 
minutes. 
+
+
+### Configuration
+add the following configuration:

Review Comment:
   Thank you very much for your work. Currently I maintain a bookie cluster 
with 200 nodes. I applied the following speed limit PR. The bookie process 
disabled autorecovery and deployed about 10 AutoRecovery processes 
independently.
   https://github.com/apache/bookkeeper/pull/2778
   
   So far, the cluster service operation and maintenance work are relatively 
good. I think you can separate the AutoRecovery service and set the 
corresponding replication limit, which may help you.
   
   For the work of this proposal, by individually limiting the frequency of 
reading zk, the zk service can be reasonably limited and protected, but it is 
not convenient to limit the byte rate of reading and copying entries because 
the size of the entry changes;
   On the contrary, I feel that PR #2778 can protect zk's read speed through 
speed limiting.
   
   Let's hear what others have to say.
   



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