You can certainly use Port Mirroring with the HP 2915. You can find the information for port mirroring on page B-23 in the documentation for the 2915.
You will be able to designate monitoring of inbound and outbound traffic on either individual ports, groups of ports, static port trunks, and one static VLAN.
An example to assign a port as the monitoring port:
> ProCurve(config)# mirror-port 8
Removing port 8 as the monitoring port:
> ProCurve(config)# no mirror-port
Once you assign the monitor port you can then select the source interfaces:
> ProCurve(config)# int 1-4, monitor
To show the current monitor (this will display what port is the monitor port, called the mirror port, and what the sources being monitored are)
> ProCurve(config)# show monitor