Issue when Migrate from single disk to RAID5 - TS420

[kknd007]

got my ts420 (running the latest firmware updated 2 days ago) to replace the aging ts409, had 4 disks in ts409 running raid5, 2 disk @ 1.5t each, 2 disk @ 2t each

i took the simple approach of inserting a 2tb disk into ts420, and copied all files from ts409 to ts420.

then inserted 3 disks into ts420.

so the drive sizes in ts420 is as below:

disk1 - 2tb (holding all the data totalling less than actual 1.5tb drive size, i checked disk usage, about 3gig less than the actual 1.5tb drive size)
disk2 - 1.5tb
disk3 - 2tb
disk4 - 1.5tb

here's the problem

when i select disk1 as the source disk, and try to migrate to raid5, only disk3 shows up after clicking the next button, and can only do raid1

when i select disk2 as the source disk, all disks show up after clicking the next button, and can migrate to raid5.

however, since all my data is on disk1, the 2nd scenario will wipe out all my data...

my question is, why can't i do raid5 selecting disk1 as the source disk. i know it's a 2tb drive, but amount of data is less than 1.5tb, in theory we can mix n match drives of different sizes don't we(with the smallest drive size being used as common size). and in my qnap409 it works fine.

[doktornotor]

This is not how you migrate. Kindly read the fine manual.

1/ Migrating from Old NAS
2/ Online RAID Level Migration

If you migrate a 2TB single volume disk to another NAS, you can NEVER use smaller drives for subsequent RAID level migration/capacity expansion. That's how RAID works, duh! Disk usage is totally irrelevant. It can never be smaller even if the drive was totally empty.

[kknd007]

ye read the old nas migration article before, doesn't have 409, too old to migrate, hence the copy method...

looks like i'll have to copy again to the small drive and then migrate my way up to the 2tb lol

cheers.