Choosing Data Storage

The type of data storage determines the historical data access performance and the amount of historical data that can be stored in the system. Data storage configurations are also important for system availability and recovery.

Storage Size

The data storage must have enough space for the different programs and applications that are running on the computer. This includes space for the historical data that is recorded by the system and some free space as a buffer.

The following table shows the estimated storage space that is required, without the historical data logs. The estimates are rounded up and allow for updates and system maintenance.

Component	Storage Space
Windows Operating System software	100 GB
Microsoft SQL Server software	2 GB
PME software	5 GB
PME system databases	5 GB
PME historical database	(see below)
Free space	30% of the storage size

PME historical database

The storage space that is required for the historical database (ION_Data), is equal to five times the size of the main database file (ION_data.mdf):

Storage Space for ION_Data (GB) = 5x .mdf (GB)

It can be broken down into the following components, where ION_data.mdf size is the estimated maximum size when PME is in steady-state:

Component	Storage Space
Main database file (.mdf)	(1x) ION_data.mdf size
Transaction log file (.ldf)	(1x) ION_data.mdf size
Last two full backups	(2x) ION_data.mdf size
Free Space for Backups or tempDB	(1x) ION_data.mdf size
Total	(5x) ION_data.mdf size

Optionally, the component can include storage of archive database when data archive and / or trim strategy is performed. For medium to large systems (250-2,500 devices), we recommend you to perform data archive and / or trim strategy to support healthy database. See Archive and Trim strategy for more information.

NOTE: Use the Database Growth Calculator tool to estimate the database size for 'n' years of archive data. The tool is available through the Exchange Community. See Resources for link information.

The estimates above are based on the following assumptions:

The .ldf file is typically just 10% of the .mdf size, but occasionally expands to 100% during normal operation.
The system default is to keep two database backups.
100% of the .mdf size is required for free space. The tempDB will occasionally expand to 100% of the total .mdf size, but not at the same time as a backup. If the backups and tempDB are on different hard drive groups, each of them require x1 .mdf in hard drive space.

Main Database File Size (ION_data.mdf)

Unlike the system software, the historical database size is continuously growing. Its size and growth can be estimated based on the amount of:

Also, the database is configured to automatically grow by 10% when required to create room for additional measurements. This growth operation can occur at any time and you need to consider it in the database size calculations.

NOTE: Use the Database Growth Calculator tool to estimate the database growth for your system. The tool is available through the Exchange Community. See Resources for link information.

For optimum performance, minimize database auto-growth by configuring the database container to the estimated maximum size after growth. During commissioning, use the Database Growth Calculator tool to estimate the maximum ION_Data database size based on your data retention policy, and configure the database container to the estimated maximum value. For example, if the ION_data database file is estimated for 2 TB and above in container size then split the database in to multiple files. For more details on how to set database container size and / or to add new files to be database, see Increase the Size of a Database. You can view the size of the ION_Data database using the Database Manager tool.

Storage Performance and Availability

Storage Type

The two main storage solutions that are available are Hard Disk Drives (HDD) and Solid-State Drives (SSD). HDDs are good at providing cheap, bulk storage for non-performance critical data. SSDs are good at providing strategic storage for high performance data. We recommend that you use SSDs for the Microsoft Message Queuing (MSMQ) storage in medium, large, and extra large PME systems.

Storage Configuration

Storage drives can be configured as single drives or a number of separate drives. For a small Basic Systems, a single drive is sufficient. For all other systems, we recommend that you divide the data storage into different drives.

For medium to large systems (250-2,500 devices):

Drive Type	Components
SSD	Software: OS, PME, SQL Databases: ApplicationModules, ION_Network, ION_SystemLog MSMQ
HDD or SSD	SQL tempdb
HDD or SSD	ION_Data
HDD or SSD	ION_Data.ldf
HDD or SSD	ION_Data archive database, database backups

RAID Systems

In addition to separating the software components into different drive groups, redundant arrays (RAID) can be used to improve performance and add simple redundancy. In a RAID 1 configuration, one drive is a complete copy of a second drive. If either of the two drives stops operating, the other takes over without any data loss. The faulty drive can then be replaced to restore the RAID configuration.

Recommended RAID 1 configurations:

2x Drive

Component	Group 0
Component	Drive 1+2
OS	ü
tempDB	ü
MDF	ü
LDF	ü
Backups and archive	ü

4x Drive

Component	Group 0	Group 1
Component	Drive 1+2	Drive 3+4
OS	ü
tempDB		ü
MDF	ü
LDF		ü
Backups and archive		ü

6x Drive

Component	Group 0	Group 1	Group 2
Component	Drive 1+2	Drive 3+4	Drive 5+6
OS	ü
tempDB	ü
MDF		ü
LDF			ü
Backups and archive			ü

8x Drive

Component	Group 0	Group 1	Group 2	Group 3
	Drive 1+2	Drive 3+4	Drive 5+6	Drive 7+8
OS	ü
tempDB		ü
MDF			ü
LDF				ü
Backups and archive				ü

NOTE: Plan for system growth by having a computer with space for additional drives. This makes it easy to add additional storage as the system grows.

NOTE: It is possible to use other RAID configurations, such as RAID 0 or RAID 5. These configurations are not discussed in this document.