The historical values of the PI Tag can get stored. This is configurable when you create a publication. For more info, please see this link.
For bandwidth or performance issues, PI Cloud Connect can sustain a data transfer rate of approximately 4,000 events/sec per node . When publishing or subscribing to data at a rate of 4,000 events/sec, 120 Kbytes/sec of network throughput will be utilized on a constant basis. As a comparison, average OSIsoft customers have data rates for their PI Interfaces of about 50 events/sec per 1,000 PI points. Given an average customer, the bandwidth required per thousand (1,000) PI points is approximately 2.9 Kbytes/sec.
Is the historical value/ current value getting stored in AF data base or PI server. If it is in PI server, appropriate tag security needs to be configured?
Both are stored in the PI Data Archive. The PI Connect Node uses AF SDK to write to the PI Data Archive. The required permissions for the PI Connect Service account are
Service Account Permissions
•PI (pub: read; sub: write)
•AF (pub: read; sub: write)
You could do this through a mapping or trust to the PI Data Archive.