well, performance should not be a problem as long as you do not pull or push huge data for each request between the servers
Performance also depends on your network bandwidth, which will be the bottleneck.
Ever needed a SQL 2008 Database replicated/mirrored/log shipped on another server but you can't take the downtime inflicted by initial snapshot or disconnect while T-logs are restored or mirror applied?
You can use SQL Server Initialize from Backup…
This video shows, step by step, how to configure Oracle Heterogeneous Services via the Generic Gateway Agent in order to make a connection from an Oracle session and access a remote SQL Server database table.