Determine the disk volume requirements

We recommend a minimum of two local volumes for your deployment, with each volume comprised of separate disk arrays (for example, RAID) or connected to redundant storage devices through a high-speed Storage Area Network (SAN). Optimum configuration of Data Archive involves having five local volumes, one for each task shown in the following table:

The PI Server install kit allocates an archive size based on the number of licensed points and RAM. The recommended archive size will be (approximately) 1/3 the physical memory or 3*LicensedPtCount/1024 MB (whichever is smaller).

Depending on how many volumes you have available for your Data Archive, refer to the following recommended disk volume deployment scenarios:

PI Archives are the files that the PI Server uses to store PI data. Each archive file contains events for a time period specified by the archive start time and end time. By default, automatic archive creation is enabled. During installation, a single archive is created with the name of the form COMPUTERNAME_YYYY-MM-DD_HH-MM-SS.arc. The start time of this archive will be midnight corresponding to the day that the Data Archive server was first started.

If you do not want to enable auto-archive creation for an installation, specify a certain number of archives to be created as part of the install. The archive files names in this case will be piarch.001, piarch.002, piarch.003, and so on, by default.Piarch.001 will have a start time of midnight and the remaining archive files will be empty.

For more information, see the PI Server topics in the Data Archive Administration guide.

PI Snapshot Subsystem receives all the new data events for all PI points, regardless of the sending application. The event queue is a buffer that consists of one or more files that store events that are destined for storage in a PI archive file. PI Snapshot Subsystem writes events into the event queue, and PI Archive Subsystem reads events out of the event queue. The event queue protects against data loss due to disruptions in communication between the Snapshot Subsystem and the PI archive, such as an archive backup or a failure of the disk drive on which the archives are located.

By default, event queues are written to the drive with the second-most available free space, provided at least 5 GB is available. For new installations, you can override this default value and choose the event queue location.

We recommend you store the event queue on a separate physical drive from the PI archive files. Using separate drives allows data to be read from the event queue and written to the archive simultaneously, thereby optimizing data throughput.

For more information on the event queue, see Event queue and Monitor the event queue with piartool -qs.

Note: The PI Server install kit will automatically select the best drive for the archives and queues based on available disk space. The install kit specifies PI archives on the drive with the most disk space available and event queues on the drive with the second most disk space available. Archives, event queues, and PI backup should reside on separate partitions from the operating system. If you only have one additional drive (ie. C:\OS and D:\App), then specify separate subfolders on the same drive (ie. D:\PIArchives, D:\PIQueues).

1. Determine the required disk volume sizes recommended for your Data Archive deployment based on current or anticipated load and data volume.

   Note: For more details or further guidance, visit the Customer Portal.

2. Determine the disk volume resources available for your Data Archive install.

   Consult with your IT department to determine how much hardware you have available.

3. Determine whether you have enough storage resources available to allocate your files across five separate disk volumes for optimal performance.

   Using a separate volume for each task distributes disk I/O for dedicated tasks and allocates a well-defined amount of disk space for each task. If Data Archive is connected to a SAN, the SAN distributes disk I/O whether or not the PI Server is installed on multiple volumes, but you should still use multiple volumes to allocate disk space for each task.

4. If you do not have access to five separate disk volumes, ensure that you have at least two separate disk volumes available for your deployment as a minimum requirement.

   By default, the install kit specifies the following directory paths for your file location:

   • Data Archive binary files are installed in %ProgramFiles%\PI\bin.

   • Archive files are installed to the volume with the most available free space.

   • Event queue files are installed in the volume with the second-most available free space, provided at least 5 GB is available.

5. Enter the file path for the Data Archive installation directory in your PI Server installation worksheet.

   For example: %ProgramFiles%\PI. After the installation, the PISERVER environment variable will correspond to the installation directory.

   Note: This value will be required by the install kit later during the installation.

6. Record the file path for event queues in your PI Server installation worksheet.

   Do not use %PISERVER%\dat. We recommend not using the drive where PI archives are stored if you have enough allocated disk drives available.

   Note: This value will be required by the install kit later during the installation.

7. Record the file path for PI archives in your PI Server installation worksheet.

   Do not use %PISERVER%\dat. Avoid specifying the drive where PI event queues are stored. Ensure that the location of the PI archive directory contains enough free space to create three archives. The location for archives is typically on the largest drive on the server.

   Note: This value will be required by the install kit later during the installation.