Demystifying Hardware - SQL Server 2012 Internals and Troubleshooting - page 51

SUMMARY
As you go through the process of evaluating, selecting, sizing, and coni guring your database hard-
ware and storage subsystem, it is extremely important that you are familiar with the characteristics
of the type(s) of workload that your system will be handling. Different types of workloads and
mixed workloads place varying demands on your server hardware and storage subsystem. You need
to take this into account early in the process, as it inl uences many of your decisions.
After considering your workload, you need to decide whether you want an Intel or an AMD-based
database server, as that dictates which model servers from your selected system vendor are eligible
for consideration. Unfortunately, given the relatively poor single-threaded performance and high
physical core counts of the last two generations of AMD Opteron processors, it is very hard to jus-
tify their use with SQL Server 2012 Enterprise Edition, even after considering the SQL Server 2012
Core Factor Table license discounts. If AMD continues to be unable to compete in the high end of
the market, it will reduce the incentives for Intel to maintain their aggressive product release cycle,
and slow the pace of innovation. This will be bad for the IT industry in the long run.
After selecting your processor vendor, you need to decide whether your workload and volume
requirements dictate the use of a one-, two-, four-, or eight-socket database server. With the latest
generation of processors and improved memory and storage densities, many smaller SQL Server
workloads may be able to run quite well on a single-socket database server.
Because processors have become much more powerful, and memory and storage density have
improved over the past several years, it has become increasingly feasible to use two-socket servers
for database usage. Intel continues to release newer-generation processors more quickly in the
two-socket space, and the equivalent generation Intel two-socket processors have better single-
threaded performance than their Intel four-socket counterparts. This means that you may be
able to run a much higher percentage of SQL Server workloads on a two-socket server, rather
than a four-socket server, and save a great deal of money in SQL Server license costs. Despite
these improvements in the two-socket space, some workloads still require more resources than
you can obtain from a two-socket server. If you need even more RAM, PCIe expansion slots, or
total processor cores than you can get in a two-socket server, you have to make the jump to a
four-socket or larger server.
With the new core-based licensing in SQL Server 2012 Enterprise Edition, you need to pay much
closer attention to your physical core counts and the relative performance and scalability you get for
each physical core. You are likely to be stuck with the processor(s) you choose for the lifetime of the
server, which is probably several years, so choose wisely. Choosing wisely means getting the most
performance and scalability with the lowest total physical core count in the server. Choosing poorly
means getting less performance and scalability but paying the same or a higher total cost for your
SQL Server licenses. Put some serious thought into your processor decision, using benchmark results
to help justify it.
Because server RAM is relatively inexpensive, with costs continuing to decline, it makes sense to
get a large amount of RAM, subject to any SQL Server license limits. Both SQL Server 2008 R2
Standard Edition and SQL Server 2012 Standard Edition have a license limit of 64GB. Physical
RAM is an inexpensive, partial substitute for I/O capacity. If you have enough physical RAM that