can multiple splunk indexers share the same physical LUN without corrupting each others data?
No, LUNS cannot be shared. That is not a Splunk limitation, it would be analogous to sharing a single hard drive between two computers.
If you need to share between two operating systems, you will need to utilize a shared filesystem, using a protocol such as CIFS (Windows) or NFS. This is commonly referred to as NAS (Network Attached Storage).
