Hello,
I Have a QNAP TS-421 Nas with RAID5.
I have 4 WD Disk WD20EFRX TBs.
I want to buy a new NAS, TS-464 for example, to improve performance.
I want to know if migration from QNAP-TS421 to TS-464 is possible, without Data loss, and if i can easily place my 4 WD disk in the new as with same configuration.
I’m not sure if there is a mode operation because QNAP TS-421 is quite old.
Thanks for your answers 
While possible, do not migrate old CAT1 disk to a CAT2 device, it will result in a crippled legacy volume that has many limitations.
Setup the new NAS with new disks and then copy the data over (afterwards use the old NAS as a backup, as you always need backups..a RAID is NOT a backup!)
Thanks for your answer.
If I understand, U have to buy new disks and then copy/paste my data from old NAS to new one to avoid legacy limitations.
Migrating old disks and RAID volume from TS-421 to TS-464 is possible, but limited ?
I have to do this, or I’ll have to buy new disks ;(
On top.. how is your backup situation ? (no, a RAID is NOT a backup)