RES WM - High Availability for SQL Server

RES Workspace Manager High Availability for SQL Server All other product and company names mentioned may be trademarks and/or service marks of their respective owners. the United States and other countries. Virtual Desktop Extender and RES VDX are trade names of Real Enterprise Solutions Nederland B. RES Software provides the publication "as is". Subject to this disclaimer.V. RES Automation Manager. RES Software is not liable for any damage which has occurred or may occur as a result of or in any respect related to the use of this publication. Pat. P. suitability for a different purpose or otherwise. RES Software may change or terminate this publication at any time without further notice and shall not be responsible for any consequence(s) arising there from. The Netherlands. 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Dynamic Desktop Studio.433. in Europe. 2|Page . ..........................................RES Workspace Manager ...........................................................High Availability for SQL Server Introduction ........... 6 References 7 High Availability Scenarios Single Datastore (HA) Multiple Datastores (Multisite configuration) Further considerations regarding High Availability 7 7 14 16 3|Page ................ 4 RES Workspace Manager Datastore ................ 5 High Availability Techniques .............................................................................................................................. the Datastore contains all information required to build the user’s dynamic desktop. One of the first steps in setting up an RES Workspace Manager environment therefore is to connect to a database server and create an RES Workspace Manager Datastore on it.RES Workspace Manager . RES Workspace Manager supports the following database server types:     Microsoft SQL Server (2000 and later. the high availability of an RES Workspace Manager Datastore is directly related to the type of database server on which it is located. 4|Page .0 and later)  This whitepaper covers the different levels of high availability scenarios using RES Workspace Manager 2011 with Microsoft SQL Server 2008 R2. Because of this. including Express editions) Microsoft SQL Azure Oracle (9i and later) IBM DB2 (8.1 and later) MySQL (5.High Availability for SQL Server Introduction In RES Workspace Manager. Desktops and laptops to use a single database or you can use replication to set up multiple databases. The RES Workspace Manager Console communicates directly with the RES Workspace Manager Datastore.RES Workspace Manager . You can set all your Terminal Servers. RES Workspace Manager stores all configuration data and resources in an SQL-based database: the RES Workspace Manager Datastore. All RES Workspace Manager Agents receive a local cache of the RES Workspace Manager Datastore and communicate with their cache rather than directly with the RES Workspace Manager Datastore. Each RES Workspace Manager Agent uses its cached data instead of connecting to the SQL database directly. let’s talk about the communication model used by RES Workspace Manager. The local cache stores configuration data that is received from the Datastore.High Availability for SQL Server RES Workspace Manager Datastore First. 5|Page . the information remains in cache until the Datastore is able to receive it. This downstream communication is asynchronous: if the Datastore is busy or unavailable. sends this data from the local cache to the Datastore. This upstream communication is also asynchronous: if the database is busy or unavailable. Any changes made via the console are obviously not accepted.High Availability for SQL Server The local cache also stores user information (log files and monitoring data) that is collected by each RES Workspace Manager Agent. the request is deferred until the Datastore is able to process it. The RES Workspace Manager Datastore also stores the user information (log files and monitoring data) that is collected by all RES Workspace Manager Agents. The above mechanism plays a crucial role in allowing administrators to recover the main SQL server while end users are still working seamlessly. The RES Workspace Manager Agent Service. which runs on each RES Workspace Manager Agent. Local caches are updated through selective synchronization: the RES Workspace Manager Agent Service retrieves only changed information from the Datastore and places it in the local data cache.RES Workspace Manager . The RES Workspace Manager Agent Service pushes each Agent's log files and monitoring information from the local cache to the Datastore. High Availability Techniques The tools used to create resiliency and build a high availability protection around a Datastore hosted into a Microsoft SQL Server are:   Replication Backup and Restore Virtualization  6|Page . This reduces the load on the central Datastore significantly. but in the end the aim to is to get the service back online as soon as possible or at least within a predefined SLA.High Availability for SQL Server References Introduction to Backup and Restore Strategies in SQL Server Planning for Disaster Recovery SQL Server Best Practices Hardware and Software Clustering solutions: Getting Started with SQL Server 2008 R2 Failover Clustering Installing a SQL Server 2008 R2 Failover Cluster SQL Server 2008 Failover Clustering SQL Virtualization: SQL Server on VMware vSphere – Best Practice Running SQL Server 2008 in a Hyper-V Environment . which is already installed.Best Practices and Performance Recommendations Virtualizing Microsoft SQL Server 2008 with Citrix XenServer High Availability Scenarios Depending on the environment the disaster recovery process can be different.RES Workspace Manager . most importantly. stable and. The disaster recovery method used is to have a “hot” standby server (SQL2). Single Datastore (HA) The most common scenario of an RES Workspace Manager setup is when only one Datastore is present within the infrastructure. The standby server should already have the most recent operational databases fully-restored in no-recovery mode. 7|Page . is an exact copy of the production server's configuration. Product Type] Same as SQL1 9 Gig 2 AMD (x64) C(#G).1 1.2 1.RES Workspace Manager .3 1. of CPU’s CPU & Speed Drives Hard Disk Space 8|Page .D(#G) SQL2 (storage replication partner / hot standby restore-subscriber) 1. Product Type] 8 Gig 2 AMD (x64) C(#G).5 Drives Server Type System Model RAM Memory No. depending on your archiving needs.4 1. of CPU’s CPU & Speed Hard Disk Space Windows 2008 R2 [Server Model Number.D(#G) This server should have terabytes and terabytes of space.3 1.2 1. 1.4 1.5 System Model RAM Memory No.1 Server Type Windows 2008 R2 [Server Model Number.High Availability for SQL Server SQL1 (production instance) 1. the Datastore is populated with the tables needed to perfom day to day tasks. As soon as the connection is established.RES Workspace Manager .High Availability for SQL Server Above is a typical scenario in which the RES Workspace Manager Console connects to the first SQL server presents in the environment. 9|Page . we used the built in SQL tools to recreate the above tables (now empty) of the RES Workspace Manager Datastore in a new Datastore present on the second SQL server. 10 | P a g e .RES Workspace Manager . The steps below outline the procedure used to script the original database.High Availability for SQL Server As tested in our labs. allowing the administrator to quickly and easlily scale this solution across the environment. During replication. 11 | P a g e . This user should always be used to connect the Agents to the Datastore. but its tables will be empty. easing administration and scalability. making sure that a Datastore with the exact name as on the production server exists already.High Availability for SQL Server The script can be saved to clipboard or to a file.RES Workspace Manager . who is owner of the RES Workspace Manager Datastore. It is also imperative to create an SQL user on each database servers.The script should then be run as a new query on the second SQL server.The new Datastore will have the same structure of the original. the appropiate information will then be added. RES Workspace Manager . the normal stream resumes re-establishing the correct update/change model as described by Microsoft. DNS alias should then be changed back to the production database and DNS entries for each Agent flushed. 12 | P a g e . pointing to the production Datastore. the administrator can easily point the alias in the DNS console to the DR Datastore.High Availability for SQL Server The scenario below shows the complete setup. with the Agents connecting to a DNS alias. The Publisher/Subscriber model described in the attached document does not support a direct change to rows: when the production Datastore comes back online. minimizing downtime for the end user while recovering the primary Datastore from backup tapes. Please make sure that DNS entries for each Agent are updated using the appropriate command. In the event of failure of the primary Datastore. Production Mode DR Mode It is critical during downtime of the production Datastore to prevent making any changes via the RES Workspace Manager Console while the Agents are connected to the DR Datastore. using the appropriate commands. com/workspacemanageradminguide/14277.21) 13 | P a g e .htm http://support. ensuring that communication amongst the SQL servers and the Agent works flawlessly.ressoftware. As best practice SQL communication should be as described in the figure below: DHCP can also be used for an automatic discovery of the online SQL server. The Workspace Manager Admin Guide gives you a step by step instructions on how to set this up.com/workspacemanageradminguide/14783.ressoftware. You can find this information at: (http://support.RES Workspace Manager .aspx?DownloadGuid=5a0 8a3de-443b-e011-85a9-005056bb474c (pag.com/Modules/Downloads/Eval.htm http://support.High Availability for SQL Server It is also critical to have a resilient. tested and proven DNS infrastructure.ressoftware. 14 | P a g e .RES Workspace Manager . In this scenario. a master Datastore and site/branch Datastore are deployed to increase security. guarantee performance and load balance the master Datastore processing.High Availability for SQL Server Multiple Datastores (Multisite configuration) Another more complex scenario is when RES Workspace Manager is configured to work in a multi-site/branch office environment across the WAN. enabling key enterprise clients to run successful businesses. Instead it functions as a master repository to feed the branch offices Datastore. not only the central but also for each branch Datastore. This method requires a more complex design in terms of replication. a full back up should be schedule at least once a week (off peak hours to minimize performance degradation). A monthly back up is also recommended. An HA design around.High Availability for SQL Server In this scenario. It is also necessary to have a backup strategy in place for the main site as well as the remote sites to ensure proper redundancy of data.RES Workspace Manager . is essential to make the RES Workspace Manager service resilient. to work in a HA situation. Agents at each branch will connect to their site Datastore. To make the branch/site Datastore resilient. The local cache concept introduced at the beginning of the document still applies. The central Datastore can be made redundant by following the same technique used in the single Datastore (HA) explained previously. typically late in the evening). the central Datastore is not contacted directly by all Agents. 15 | P a g e . As general guideline. a similar technique to the single Datastore (HA) can be used. A manual intervention by the administrator is however needed to replace the FQDN name in the DNS Alias. We stress the importance of having DNS integrated into Active Directory to make sure records are dynamically updated. Tailoring this strategy to your environment is key to a successful redundancy solution. and a differential back up once a day (also scheduled to run off peak hours. Moreover. the considerations made previously regarding a stable and proven DNS infrastructure are even more important in this scenario. Nonetheless RES Support is committed to share knowledge and advice regarding critical areas of the infrastructure such as SQL. 16 | P a g e .RES Workspace Manager .High Availability for SQL Server Further considerations regarding High Availability The table below shows guidelines for high availability options beyond the scope of this document.