DSLB™ - Database SQL Load Balancer
DSLB™ is designed to tackle SQL load balancing issues for business intelligence (BI) applications. Our unique dedicated SQL load distribution algorithms eliminate poor performance scalability; poor SQL Server failure handling and can eliminate planned service downtimes.
DSLB™ elevates query load balancing technologies to a new level: transaction loads can be distributed by sessions or by query. Unlike network load balancers, which were designed for distributing stateless network-bound queries, DSLB maintains concurrent client-server session states at all times. Therefore, using session-based distribution algorithm, any applications requiring temporary database objects (with updates) will work flawlessly. Any SQL Server® in the cluster can be taken offline for repair without ever shutting down service. Query-based load distribution is optimal for stateless web traffic. SQL Server® fault tolerance is automatic. It also allows cluster expansion with zero downtime.
How DSLB™ Works:
DBx™ is an industrial-strength intelligent database packet processor (gateway). It resides on the network path between database clients and a cluster of database servers. The system will run on a dedicated appliance or as a service co-locate with a SQL Server®. It can be protected using built-in IP-takeover to eliminate the single-point-failure. For most applications, deploying DBx™ is a plug-and play operation. Cluster configuration and monitoring are done through a Windows-based Control Center.
Key Features:
HIGHER PERFORMANCE AND WIDER RANG OF APPLICATIONS
Comparing client IP-based load balancing and network-based load balancers to DSLB's session-based load balancing, DSLB session-based load balancing can deliver finer balancing granularity which means higher overall performance. DSLB can distribute query loads by sessions or by individual query; therefore it can handle wider range of applications than typical network load balancers.
NON-STOP SERVICE
Since DSLB maintains session states at all times, SQL Server fault tolerance is easily obtained by a simple re-do logic in the application's error handling code. Every SQL Server in the cluster can be taken offline for repair and reconnected for load sharing without ever shutting down the cluster.
SCALABILITY
DSLB gateway comes with a built-in automatic dataset resynchronization tool. You can add SQL Server or rebuild a corrupted SQL Server without ever shutting down the cluster.
PROACTIVE MONITORING FOR SECURE DATA ACCESS
DSLB constantly monitors the health of all database servers by looking for telltale signs of failure. It also monitors all incoming network traffic. Only queries from legitimate sources are to be accepted.
ELIMINATES ALL SINGLE POINTS OF FAILURE
DSLB Load Balancer can be protected by IP-takeover for LAN environments or by DNS for WAN environments.
SERVER CONSOLICATION FRIENDLY
DSLB Load Balancer can be installed as a network appliance or co-locate with SQL Server or other services. It saves you money by leveraging all SQL Server resources for your mission critical applications.
Current Offerings:
- Standard Edition - 200 or fewer concurrent connections, supports up to 4 servers in a cluster.
- Enterprise Edition - 500-6000 concurrent connections, supports up to 16 servers in a cluster.
System Requirements:
Operating System: Windows NT/2000/2003 Servers, Standard or Enterprise Editions.
Database Support: SQL Servers 2000 and 2005, Standard and Enterprise Editions.
Download the DBx™ SQL Load Balancer (DSLB) brochure (PDF, 197 Kb)
Query Load Balancing - Performance Boost for BI Applications
For business intelligence (BI) applications, heavy calculations make query load balancing crucial in effective use of SQL Server resources. Complex BI applications need sophisticated manipulation of database objects before generating reports. These are not pure read-only applications. "Sticky" load distribution algorithm is required to ensure the correct operations.
Network load balancers are designed to distribute stateless web traffic. They typically use cookies to maintain client session states. They lack continuous session management capabilities. This affects the effectiveness of their load balancing algorithms and can require application code to directly monitor individual SQL Server states.
Load balancer is a by-product of DSLB™. It manages all concurrent client-SQL Server sessions. It can distribute query load based on sessions or individual queries. It responds immediately to all SQL Server state changes. Applications with proper re-do error-handling logic are automatically SQL Server and DBx™ fault tolerant.
DBx™ failures are protected by built-in IP-takeover function for LAN deployments and by DNS for WAN deployments.
A unique feature in DSLB™ is that it allows adding SQL Servers using an automatic resynchronization tool without shutting down service. This also allows individual SQL Servers to be taken offline for repair and resynchronized without affecting cluster service status.
In the DSLB™ load balancer, there are four load-balancing heuristics: round robin, least server load, least waiting query and least waiting connections. Adjusting the "performance coefficient" for individual SQL Servers can further customize each of these algorithms.
