"Will SQL Server 7.0 scale to meet my requirements?" I'm frequently asked this question by people who, for example, are running a DEC VMS system that supports 350 users, and their company is considering migrating to SQL Server 7.0. Or they're running an AS/400 system that supports multiple locations with more than 500 concurrent users, and they're looking at moving their new applications to Windows NT and SQL Server.
Considering SQL Server 6.5's reputation, such questions are understandable, especially for people who aren't particularly familiar with SQL Server. Although SQL Server 6.5 provides a terrific price/performance ratio, it has limited scalability. SQL Server 6.5 is known as a great departmental system, but it isn't adequate for large-scale implementations. Although benchmark scores can be misleading, they sometimes provide valid information about maximum scalability. Many tests reflect SQL Server 6.5's performance ceilings, including the TPC-C benchmarks in which the top SQL Server 6.5 score was 16,216 tpm. This score wasn't bad. In fact, SQL Server 6.5 had the best cost-per-transaction scores, but the maximum scores were nowhere near the marks that mainframe-class systems running DB2 or Oracle achieved. (Three Oracle benchmarks have exceeded 100,000 tpm.)
SQL Server 7.0 has many features that boost its scalability beyond the departmental levels of SQL Server 6.5. SQL Server 7.0 supports databases that are up to 1,048,516TB in size—a massive increase over SQL Server 6.5's 1TB limitation. Likewise, improved SMP support lets SQL Server 7.0 take better advantage of 4-way and newer 8-way SMP systems. Recent SAP Sales and Distribution (SD) benchmarks conducted with an 8-way Profusion system at 550MHz showed an 88 percent increase in performance over earlier SQL Server 7.0 4-way results. The 8-way systems cranked out a score of 4512 SD users, improving on the old 4-way score of 2400 SD users. The SQL Server 6.5 score was 1011 SD users. Similarly, recent TPC-C tests on 8-way SQL Server 7.0 systems moved SQL Server's top TPC-C tpm marks to 40,013.
Of course, the biggest example of SQL Server's scalability is Microsoft's TerraServer database, which provides satellite photo images. Microsoft claims the TerraServer database weighs in at 1.4TB, making it the Web's largest online database. In addition to its massive size, the TerraServer database has provided 99.9 percent availability since June 28, 1998, while running a Beta 3 copy of SQL Server 7.0. So much for the weekly reboot myth.
So does SQL Server 7.0 scale? Yes. Will it scale to meet your requirements? It depends. On the appropriate hardware, SQL Server 7.0 will scale to meet the demands of most businesses. It will easily scale to meet the needs of businesses with hundreds of concurrent users. However, SQL Server 7.0 still doesn't quite reach the high levels set by mainframe-class systems. But if it did, what would be left for Shiloh to do?
