I get a funny feeling when you say that.
What do you mean by "mirroring"?
You can certainly mount an iSCSI target on multiple remote machines.
However, that does not mean that any magic is created. People will often try to mount an NTFS iSCSI volume on one machine, put some files on it, then simultaneously mount it on another machine, hoping to "share" the iSCSI volume. That doesn't work. iSCSI happily allows both machines to access the same disk, and does so correctly, but NTFS doesn't have any sort of mechanism to "share" a disk in that manner. It requires what's called a cluster-aware filesystem.
For those of us using systems like VMware's VMFS, though, yes, we routinely mount the same iSCSI volume on several hosts and the hosts use them simultaneously. Because VMFS is a cluster-aware filesystem and is designed to do that.