Merge pull request #212692 from VandhanaMehta/HAConceptsFAQUpdate

Updating HA Concepts page for FAQ

Author: prmerger-automator[bot]

articles/mysql/flexible-server/concepts-high-availability.md

@@ -145,7 +145,7 @@ If you don't choose a zone, one will be randomly selected. It won't be the one u
 If there's a database crash or node failure, the Flexible Server VM is restarted on the same node. At the same time, an automatic failover is triggered. If the Flexible Server VM restart is successful before the failover finishes, the failover operation will be canceled. The determination of which server to use as the primary replica depends on the process that finishes first.</br>
 
 - **Is there a performance impact when I use HA?**</br>
-For zone-redundant HA, there might be a 5-10 percent drop in latency if the application is connecting to the database server across availability zones where network latency is relatively higher (2-4 ms). For same-zone HA, because the primary and the standby replica is in the same zone, the replication lag is lower. There's less latency between the application server and the database server when they're in the same Azure availability zone.</br>
+For zone-redundant HA, while there is no major performance impact for read workloads across availability zones, there might be up to 40 percent drop in write-query latency. The increase in write-latency is due to synchronous replication across Availability zone. The write latency impact is generally twice in zone redundant HA compared to the same zone HA. For same-zone HA, because the primary and the standby replica is in the same zone, the replication latency and consequently the synchronous write latency is lower. In summary, if write-latency is more critical for you compared to availability, you may want to choose same-zone HA but if availability and resiliency of your data is more critical for you at the expense of write-latency drop, you must choose zone-redundant HA. To measure the accurate impact of the latency drop in HA setup, we recommend you to perform performance testing for your workload to take an informed decision.</br>
 
 - **How does maintenance of my HA server happen?**</br>
 Planned events like scaling of compute and minor version upgrades happen on the primary and the standby at the same time. You can set the [scheduled maintenance window](./concepts-maintenance.md) for HA servers as you do for flexible servers. The amount of downtime will be the same as the downtime for the Azure Database for MySQL flexible server when HA is disabled. Using the failover mechanism to reduce downtime for HA servers is on our roadmap and will be available soon. </br>