“In most enterprise environments, file serving, Web serving, and traditional infrastructure applications will have no reason to move to 64-bit for a long time,” says Jay Bretzmann, director of IBM’s xSeries high-performance division. If you’re running applications and workloads that need and can benefit directly from such massive amounts of memory, however, you’ll see a definite benefit in performance and scalability.
What applications are those? The obvious ones frequently cited are large database implementations, which can gain significant performance and scalability advantages by dumping their huge data sets directly into memory. Memory can be accessed 10,000 times faster than disk drives, so the more data that can be stored in memory, the better the query response, particularly for query-intensive decision-support systems. In particular, queries that require large data sorts will benefit if the sorting is done in memory.
A 2004 study commissioned by Dell compared OLTP (online transaction processing) performance of 32-bit and 64-bit Oracle 9i Database Release 2 on a Dell PowerEdge 2850 server running Red Hat Enterprise Linux AS 3. It found that “OLTP performance on the 64-bit configuration was observed to scale 25 percent to 50 percent better for a database cache size of 9GB in both medium and heavy workloads, compared to the 32-bit configuration.”
Scalability in number of simultaneous users is another memory benefit that is particularly important for large Web and e-commerce sites. For example, testing done by Performance Tuning (with sponsorship by Dell and Microsoft) on a quad-processor Dell PowerEdge 6850 found a limit of 1,300 simultaneous connections on Windows 2003 Server x64 running 64-bit Oracle 10g, versus anywhere from 101 to 1,000 for a 32-bit Windows/Oracle configuration, depending on the server’s extended memory configuration.
These scalability benefits were not lost on MySpace, a fast-growing music and social networking Web site running 15 billion transactions a day. “With 1,000 Web servers connecting to our database servers, we were eating up memory so fast that SQL Server was ejecting things from the procedure cache in order to handle all those connections,” says MySpace CTO Aber Whitcomb.
After migrating its connection-intensive databases to 64-bit SQL Server 2005 running on Windows 2003 Server x64, MySpace saw “a huge gain in stability,” says Aber, adding that “we’re benefiting from the space and power savings we’ve been able to realize through hardware consolidation.” MySpace also discovered another use for all that memory addressing capability: its middle-tier caching servers. “We’re now using 16GB RAM on each cache server” to rocket up its caching performance, Aber says.
All the major database vendors have either released or plan to release 64-bit versions for both Linux and Windows x64, including CA, IBM, MySQL, and Oracle. Microsoft has released a 64-bit version of SQL Server 2005 for Windows only.
More benefit than meets the eye
Other, similar applications can also benefit. “We see strong benefits for business intelligence, supply chain management, and ERP applications,” says Lorie Wigle, Intel’s marketing director for server software and technology. Data warehousing is another category that is frequently cited.