QNAP NAS Community Forum

Yes, I know, this is not officially supported. But I guess there must be a way on the shell level to use 4 x 6 TB HDDs - even when not using all of the storage.

Does anyone know how to set up a RAID-5 oder RAID-6 with 15.9TB capacity?

Thanks for any support!

of course it works, ... you just have to enter the command
but don't tell anyone ... (like all those people that tried before)

Well, I might try the $$$ option, if everything else failed.

Seriously, isn't it possible using mdadm, tune2fs, mkfs etc to create a RAID filesystem, that stays right below the 16TB limit?

Nope

open up the drives and take out a platter in each one ....

and just shave a bit off the edge - just try and keep your finger prints off the drive as it might affect read/writes

Well, believe it or not, but using only command line tools, I was able to create a RAID-6 with a usable size of 15,6 TB based on the four 6TB hard disks. So I lost an overall of 2TB usable space which is acceptable to me.

I am now starting to fill it up to the last byte and verify the integrity of the data written. This will take about 48 hours.

raid6 with 4x6tb is only 10.8 tb .........

yup raid 6 is n-2 ..that should have worked without any "command line magic"

how is the performance ?

Sorry, I meant RAID-5.

But my initial question was, if I could use this configuration for RAID-5 or -6, and everybody agreed that this will never work. Now what? Suddenly RAID-6 can be done easily without command line magic? At least not on my TS-412...

I can report performance after the data test.

with 10.8 you have raid6 ie 2x5.4

if you had raid5 it would have been over 16tb ~16.2

so not sure what your magic was but i think you might need to start again to test your theory

Raki wrote:But my initial question was, if I could use this configuration for RAID-5 or -6...

No your initial question was exactly this:

Does anyone know how to set up a RAID-5 oder RAID-6 with 15.9TB capacity?

• Apparently nobody here know how to set up a capacity limited RAID 5. I think very, very few would even consider to use an unsupported configuration as their data storage which could explain the limited experience with the configuration.
• Absolutely nobody knows how to setup a 4*6 TB in RAID 6 to give you 15.9 TB usable capacity, as anything above 10.8 TB would be magic.

As far as I know a 4*6 TB in RAID 6 for 10.8 TB usable capacity is fully supported to setup on a TS-412. If you failed to do that then you need to supply details on where it went wrong for anybody to be able to advice.

If you don't know the difference between RAID 5 and RAID 6, then read about it in the documentation and ask here if you have any questions.

P3R wrote:If you don't know the difference between RAID 5 and RAID 6, then read about it in the documentation and ask here if you have any questions.

Do you know the meaning of the word TYPO?!


Well, anyway, here's the result. The 15,6 TB RAID-5 works well. All data written were readable without any problem. Read performance is about 31 MB/s, Write is about 25 MB/s. There are some quite heavy background transcoding processes, so performance is probably not representing the possible maximum.

Thanks for your support!

Raki wrote:Do you know the meaning of the word TYPO?!

Yes I do.

Many that come to this forum have problems understanding RAID levels and when you multiple times write things that are incorrect about the characteristics of a RAID level, I can't help getting the impression that you may be a little confused about it. If you aren't, that's good for you but remember that we know nothing about you. What you write here is the only thing we have to get an idea of your knowledge and experience.

All data written were readable without any problem.

It would be extremely surprising if that had failed and that's not what I'd worry about using a non-supported RAID configuration.