Tag Archives: rtclocal

RTC, rtc and RTCLOCAL: Source of confusion


If you are new to Lync/Skype for Business Server or don’t have expertise on Microsoft UC platform, rtc can create a big confusion. RTC, rtc and RTCLOCAL are either name of database instance name or database name. One simple way to remember it, generally lower case represents database name while upper case represents instance name. These names exist in both Standard and Enterprise Edition. To know more about other databases and structure see Skype for Business Server 2015 Databases

rtc: “rtc” is a database which store persistent users data such as contact list, schedule conferences and ACL’s etc. rtc is part of RTCLOCAL instance which exist on each Standard Edition and Enterprise Edition Front End Servers.

RTCLOCAL: “RTCLOCAL” is a database instance name which exist on each Lync/Skype for Business Server. When install any Lync/Skype for Business Server role SQL Express edition is used to install automatically.

RTC: “RTC” is one more database instance name which is used to install locally on Standard Edition Server and part of the SQL Express Edition. While Enterprise Edition Server uses SQL Server for Back End database, therefore RTC database instance is part of the Back End SQL database server. Make sure RTC is not a mandatory name for Back End Server instance but while deploying SQL server either you can use RTC or any other name for instance.

Skype for Business Server 2015 Databases


Skype for Business Server 2015 databases are as same as it was in Lync Server 2013. Skype for Business Server 2015 installs SQL Server 2014 Express Edition (64-bit) for local configuration databases while SQL Server 2014/SQL Server 2012 SP2 with CU2/SQL Server 2008 R2 SP2 can be deployed for Back End databases, Archiving, Monitoring, Persistent Chat and Persistent Chat Compliance databases. Below are the graphical representation of databases placement in Standard and Enterprise Edition.

Explanation of each databases:

xds: xds is the main database of SfB Server and part of central management store which maintain the topology information, polices, configuration etc. and replicate a read only copy to each SfB server.

rtcxds: rtcxds maintains the backup for user data

rtcshared: rtcshared hosts the conferencing directory

rtcab: rtcab stands for real time communication address book and maintain the address book service information

cpsdyn: cpsdyn maintains the dynamic information database for Call Park application.

rgsconfig: rgsconfig maintains the response group configuration service data file.

rgsdyn: rgsconfig maintains the runtime data for response group configuration service data file.

xds: xds on SfB frontend server maintain a read only copy of xds database which is part of central management store and resides in SQL backend database server.

rtc: rtc store persistent users data such as contact list, schedule conferences and ACL’s etc.

rtcdyn: rtcdyn maintains dynamic user data such as presence.

lyss: lyss stands for Lync Storage Service and used to maintain HA within a FE pool. It is a blob database and abstract writes to backend database. It maintains a copy of the data within Front End servers in the pool temporarily, and delete that data once it has been delivered to the final database server. It is a replacement for MSMQ which was used in previous version of Lync. Therefore, it is part of the Front End servers and it is located under LYNCLOCAL named instance. It is also used for Archiving integration and Unified Contact Center. Currently, it supports Exchange and SQL for archiving.

lcslog: lcslog maintains data file for the retention of instant messaging and conferencing data on an Archiving Server.

cdr: cdr stands for call detail recording and maintains the call detail recording data.

QoE: QoE stands for quality of Experience and maintains the QoE data to provide best experience to SfB users.

mgc: maintains user persistent chat data.

mgccomp: maintains compliance data persistent chat.