Support for limiting IOPS for the disks

I could not find any way by which we can limit the IOPS per disk. Not through the XenCenter nor via XE command line.

I couldn't find anywhere online that XenServer supports limiting IOPS. I have also sent a mail on developer mailing list asking whether is there any provision for doing so, but so far I've got no reply.

I think this feature doesn't exist and can be valuable to the product.