We have an HP ProLiant ML350G6 running Hyper-V with 6x146GB disks in a RAID5 array. Due to a shortage of space we extended the array by adding another 2x146GB disks. This went well. However we are now running the first Windows backup (Windows Server 2008) on the disk array since we increased the volume from 500 to 700GB and it is taking a long time to backup. It is part way through and we estimate it will take 30 hours to complete. A full backup would have normally taken 7 hours. Should it take so long?