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7 BP1062 | Best Practices for Decision Support Systems with Microsoft SQL Server 2012 using Dell EqualLogic PS Series
Storage Arrays
1.2 Terminology
The following terms are used throughout this document.
DSS I/O pattern: DSS workloads typically take a long time to complete and usually require processing
large amounts of data that tend to utilize a major portion of the database server memory and processor
time. The data I/O pattern is predominantly sequential and usually consists of large blocks, typically
ranging from 64 KB to 512 KB in size. The key metric in measuring performance of DSS workloads is
throughput (MB/sec).
Group: One or more EqualLogic PS Series arrays connected to an IP network that work together to
provide SAN resources to the host servers.
Hypervisor: A hardware virtualization technique that enables running multiple guest operating systems on
a single host system at the same time. The guest operating system shares the hardware of the host
computer, such that each OS appears to have its own processor, memory and other hardware resources.
Partition (SQL Server): The table and index data gets divided into units that can be spread across more
than one filegroup. Partitioning makes large tables or indexes more manageable, as it enables managing
and accessing subsets of data quickly and efficiently, while maintaining the integrity of a data collection.
By using partitioning, an operation such as loading data from an OLTP to an OLAP system is much faster.
Maintenance operations performed on subsets of data are also more efficient because these operations
target only the data that is required, instead of the whole table.
Perfmon: Perfmon.exe is a process associated with the Microsoft
®
Windows
®
Operating System.
Performance Monitor, or Perfmon, gathers performance statistics on a regular interval, and saves those
stats in a file. The database administrator picks the sample time, file format, and counter statistics to
monitor.
Pool: Allocates storage space into partitions comprising one or more members. When a group is created,
there is one storage pool, called default and this pool cannot be deleted, but can be renamed. Members
and volumes are assigned to the default pool unless a different pool is specified. Space can be allocated to
users and applications by creating volumes, which are seen on the network as iSCSI targets. If the group
has multiple members, the group space can be divided into different pools and then assign members.
Primary data File (SQL Server): Contains the startup information for the database and points to the other
files in the database. User data and objects can be stored in this file or in secondary data files. Every
database has one primary data file. The recommended file name extension for primary data files is .mdf.
Primary Filegroup (SQL Server): The primary file and all system tables are allocated to the primary
filegroup.
Range left partition function (SQL Server): The boundary value that specifies the upper bound of its
partition. All values in partition 1 must to be less than or equal to the upper boundary of partition 1 and all
values in partition 2 must be greater than partition 1's upper boundary.