The sessions recordings are not permanently stored on the DPA. If Auto-archive for the DPA is not set (/tpam | Management | DPA | Select DPA | Auto-Archive Session Logs is NOT selected), then once the PSM session has finished, the session recording will be transferred to the primary TPAM console appliance (the video file would then be replicated out to all the cluster members.)
If auto-archive has been set, then the DPA will archive directly to the preferred archive server. If this process fails, the recording is sent to the TPAM console appliance.
When the Archive Server is back up, you can manually archive the session logs ( /tpam | Management | Session Mgmt | Session Logs | Select the session and "Archive Now" ).