Sorry Arno my last message was mistakenly sent to you only and not the list.
Thanks all for you comments.
Pascal thanks for the tip about extending one of the partition and using the free space i will do so but for now my primary problem is to create a boot partition so that i can boot and replace the old 1.5 TB with 2TB drive. as you said boot partition in GPT can be created anywhere not necessarily at start.
Number Start (sector) End (sector) Size Code Name
1 2048 7813119 3.7 GiB FD00 Linux RAID
3 27344896 1980469247 931.3 GiB FD00 Linux RAID
4 1980469248 2930276351 452.9 GiB FD00 Linux RAID
5 7815168 27344895 9.3 GiB FD00 Linux RAID
As you can see partition 2 is missing. when i am creating the new partition it is starting from the "2930276352" (+1 ending sector of partition 4)
should i create partition 2 of a size of 1 GB. and make it as a boot partition and install grup on that partition. do you think performing these steps will do the job. or i have to more in order to boot my New 2TB GPT drive.