Today we have reclaimed one LUN from Windows Server after which another existing LUN is showing as RAW disk in Windows
Could you please elaborate more about your reclaim process? may be the partition table information from the disk have gone wrong?
I've reclaimed one LUN from the Sever after which another existing LUN was showing as RAW disk though they are not related to each other.
2 possible things may lead to this issue, Either partition table is corrupted or there is problem with the reservation on the disk (I have seen the latter many times in w2k12). The latter is easy to resolve using Cluster.exe node clearpr:<disk#> (for 2012, you can use the equivalent Powershell command as cluster.exe is deprecated) but obviously you will see a disk error in cluster GUI if you have a problem with reservation.
For Partition table, MS will be the best to help you on this. They will restore the partition table using their tools (like diskprobe.exe )
I cannot tell exactly the root cause of the issue from what you said, My recommendations is to run EMCreports on the server and open a case with EMC support for further investigation.
You can download EMCReports from this link: ftp://ftp.emc.com/pub/emcgrab/Windows/