Introduction

A distributed OSI PI Historian is a like a sensitive musical instrument. A little knock here, exposure to the sun there and some excessive humidity can render it out of tune. In the OSI PI case working with VMWare snapshots, not properly shutting down the storage sub system or remote data collection interface and having the computer clocks not synchronized can corrupt the buffer, cache and archive files. Luckily there is an easy fix for it that is also documented in the user guides:

Historian Server System Management Guide.pdf (Page 48)

Historian Buffer Subsystem User's Guide.pdf (Page 15)

Disclaimer

This blog post summarizes the necessary steps that you can try to hopefully get your historian working again. Data loss in this particular situation is un-avoidable. Make sure to make backups of everything. E.g. create a VMWare snapshot of your server and interface system. Practice and test these procedures first on a development system. Consult technical support before using this procedure on a production system, because they might be able to get your system going again without loss of data.

Cleaning up the server

On the server first stop the PI Snapshot Subsystem and PI Archive Subsystem services.

Figure 1: Stop Archive and Snapshot subsystems

Then in your Server\PI\dat folder rename the event queue file called pimapevq.dat to e.g. pimapevq.save.

Figure 2: Rename your event queue file pimapevq.dat

Next start the Archive and Snapshot Subsystem services again.

Cleaning up the Interface and Buffer machine

On the Interface and Buffer machine stop all services that start with PI*. (See screenshot below)

Figure 3: Stop all PI* services

Then stop all services that start with FTLD*. (See screenshot below). If you have other interface types configured, then of course stop the appropriate services as well.

Figure 4: Stop all FTLD* services

Then navigate to the Server\PIPC\DAT folder and delete the following files:

• pibufmem.dat
• pidigst.dat
• pidignam.dat
• pibufq_servername.dat
• pibufq_servername.####.dat

See the screenshot below for the purpose of each file.

Figure 4: Buffer subsystem files

Next reboot the Interface and Buffer subsystem computer. Your historian should be storing values again.

Ausblick

I hope these steps are going to  work for you.