ControlLogix: Is There a Hard Disk Drive Option?

Currently have a couple of redundant "PI Collector" desktop PCs gathering PLC data in case their respective PI Server goes down or reboots. They're in between the PLCs and the servers. Rockwell performed some maintenance on one Collector yesterday while the other was apparently *not* collecting data, and the result was 23 hours of lost PLC data!! Went for years without these "Collectors" without any real problem. PLC data went directly to Servers running PI. Since adding the "Collectors" in between, have lost data a couple of times now.

DCS has HDD circular buffer which solves this problem. Up to 3 or 4 days can be stored, but that includes doing collection based on trigger criteria downloaded from each application. Would be nice to have a similar arrangement on each PLC, but it's probably never done anywhere, right?

http://www.rockwellautomation.com/rockwellsoftware/products/factorytalk-historian-me.page

However, I would be concerned with why my uniint failover, well failed.

1756-HIST1(2)G

http://literature.rockwellautomation.com/idc/groups/literature/documents/pp/ftalk-pp035_-en-p.pdf

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1756-um106_-en-e.pdf