Jtdylktuy

Various server rentals are nowadays are selling servers with let's say 4 drives.. eg: 4 x 2 TB drives..

By default they install their os inside the 1st HD..

So I have

sda - with / mountpoint 64 gb ext4 partition, 4 gb swap, empty the rest

sdb - empty

sdc - empty

sdd - empty

Sadly they didn't provide a 5th drive where could install OS separately putting all the 4 drives directly in raid without mess.

I would like to know if it's possible to:

1) Convert my existing debian 9 installation inside sda to a raid 1 spanned across the 4 drives in order to increase read performances

So my installation would turn in something like:

sda - RAID 1 sda,sdb,sdc,sdd( with / mountpoint 64 gb ext4 partition ), 4 gb swap, empty the rest

sdb - RAID 1 sda,sdb,sdc,sdd( with / mountpoint 64 gb ext4 partition ), 4 gb swap, empty the rest

sdc - RAID 1 sda,sdb,sdc,sdd( with / mountpoint 64 gb ext4 partition ), 4 gb swap, empty the rest

sdd - RAID 1 sda,sdb,sdc,sdd( with / mountpoint 64 gb ext4 partition ), 4 gb swap, empty the rest

2) Then create a raid 10 with all the remaining partitions free space obtaining

sda - RAID 1 sda,sdb,sdc,sdd( with / mountpoint 64 gb ext4 partition ), 4 gb swap, RAID 10 sda,sdb,sdc,sdd( with /raid_space mountpoint ext4 partition with remaining space )

sdb - RAID 1 sda,sdb,sdc,sdd( with / mountpoint 64 gb ext4 partition ), 4 gb swap, RAID 10 sda,sdb,sdc,sdd( with /raid_space mountpoint ext4 partition with remaining space )

sdc - RAID 1 sda,sdb,sdc,sdd( with / mountpoint 64 gb ext4 partition ), 4 gb swap, RAID 10 sda,sdb,sdc,sdd( with /raid_space mountpoint ext4 partition with remaining space )

sdd - RAID 1 sda,sdb,sdc,sdd( with / mountpoint 64 gb ext4 partition ), 4 gb swap, RAID 10 sda,sdb,sdc,sdd( with /raid_space mountpoint ext4 partition with remaining space )

I wonder how to do this and how to copy perfectly and sync the sdb, sdc, sdd to sda for the first raid1 partition after that the 1) raid 1 is created and make it bootable.