Software RAID: Degraded Array in Linux

Good afternoon, dear habrayuzyra.
On one of the machines the following situation arose - the hard drive failed.
Since the server was going for a long time, the screws there were 80 GB each (2 pieces), and I decided to replace them with 500 GB, since there is almost no cost difference, and there will be more benefits :)
The disks are broken like this:

/ dev / sda1 * 1 6 48163+ fd Linux raid autodetect
/ dev / sda2 7 9729 78099997+ 5 Extended
/ dev / sda5 7 334 2634628+ fd Linux raid autodetect
/ dev / sda6 335 577 1951866 fd Linux raid autodetect
/ dev / sda7 578 1793 9767488+ fd Linux raid autodetect
/ dev / sda8 1794 9729 63745888+ fd Linux raid autodetect

~ # df -h
Filesystem Size Used Avail Use% Mounted on
/ dev / md3 9.2G 1.9G 6.9G 22% /
tmpfs 1010M 0 1010M 0% / lib / init / rw
udev 10M 104K 9.9M 2% / dev
tmpfs 1010M 0 1010M 0% / dev / shm
/ dev / md0 46M 33M 11M 77% / boot
/ dev / md2 1.9G 36M 1.8G 3% / tmp
/ dev / md4 60G 11G 47G 18% / var
')
The question is: how to correctly transfer the whole thing to new hard drives?
Of course, you will need to increase the / var partition, and also I want to create another section for openvz virtual machines.