Mix and match drives? RAID online expansion ease of use?

[Zumi]

Hi,

I'm looking into buying a AS-604T or AS-606T, mainly for their low noise performance and high data rate.
I'm moving over from a Drobo, so my main questions would be about the RAID online expansion capabilities:

- can I use drives of different sizes and from different manufacturers together in a single NAS to form a single volume?

- does adding these initial drives work with no manual configuration needed, in other words can I just add a few drives and they all get automatically merged together into a volume where any single drive can fail (Raid 5)? Or how many steps would that take?

- can I also expand the whole volume while using it? How does that work in practice, can I just remove my smallest drive and replace it with a bigger drive and the NAS figures out the rest? (If you think that's impossible, that's exactly how the Drobo works). If it's a bit more complicated on an Asustor NAS, can you give me a rough explanation what steps this would take?

- my main beef with the Drobo is that expanding is quite a hassle. Say I want to move from a [4 * 2TB] configuration to a [3 * 2TB + 1 * 3TB] configuration, with 5 TB filled. On the Drobo, cleaning up after the change will take about 5 days, which cannot be interrupted, and during which the fan constantly outputs about 45dB. Hardly ideal for single bedroom apartment How long would this take the Asustor? What would be the average noise during that procedure? And can the task be interrupted and restarted at any time without losing any data?

- is there a maximum range how far I can expand a volume? In other words, can I just start with 2*250GB drives and then do RAID online expansion to expand that to 4*10TB drives (when 10TB drives arrive in four years) - or is there something like "maximum elasticity of 10x the initial size"?

- can I go smaller? In other words, if I have a 4*4TB setup, filled, then remove all data and just leave 200GB on it, can I then remove two 4TB drives, one after another, then insert 2 250GB drives, then remove the other 2 4TB drives, all while still using the setup? (This is not as important if it doesn't work, but it works on the Drobo and it would still be valuable to know.)

- say I have a setup with 4*4TB drives, and I have done various RAID online expansions in the past to arrive at this setup (for example, [2*250GB] -> [4*1TB] -> [2*1TB + 2*2TB] -> [4*3TB] -> [4*4TB]). How do I recover my data from a theoretical full failure of the NAS itself? Can I just buy another Asustor unit, add the drives into this new unit and all my data automatically appears there? Or how difficult would that be?

Thanks for your answers!
Zumi

[ddaniel51]

Here are some tutorials from the ASUSTOR College that will answer your questions.

http://download.asustor.com/college/en/ ... o_RAID.pdf

http://download.asustor.com/college/en/ ... ansion.pdf

http://www.asustor.com/online/College

[Zumi]

Thanks for those links!

Unfortunately, there are still many points that are not answered, so let me ask them again:

- according to those documents, one can apparently use drives of different sizes. I might therefore assume that it's likely that drives from different manufacturers work as well. But it would be good to get a real confirmation about that.

- According to docs, with a setup of 1TB+2TB+4TB+4TB (11TB net), one can only use 3TB in such a case. Is this really the final word, or is there some option to get more usable space (for requirement "balanced")? I'm asking because with Drobo, in that case, you would get 6.35TB of Raid5-style space.

- When doing a RAID expansion, say from 4*2TB to 4*3TB, with 5TB filled, I'm still looking for a time estimate how long this would take.

- The documents also don't mention how noisy such a RAID expansion is. I have an estimate from the specs of 21.3dB(A). Can somebody from sales please confirm to me that this is indeed the noise level during such an extreme operation?

- The documents also don't mention whether the RAID expansion steps "Synchronizing" and "Capacity Expanding" can be interrupted and continued later. Is this possible or not? What happens if there is a power outage during those steps - is the data safe?

- The documents don't mention a limit to how far I can expand a volume. Can I get a spec what the biggest hard drive size is that the AS-604T and AS-606T will support in their lifetime?

- The documents don't mention the ability to shrink volumes. I assume that this is not possible, can I get a confirmation on that?

- The documents don't mention any NAS failure recovery steps. Imagine that all my drives are fine, but the NAS itself just suddenly stopped working, beyond repair. I would take out those hard drives that have still got all my data on them. What would be the solution to such a problem. As an example, could I just buy the same NAS again, insert all these drives, and the Asustor would detect that they belong together and just automatically allow access to that volume again? Or how would that work?

Regards,
Zumi

[Steve@AST]

Hi Zumi,

Regarding your inquires, I will answer them in red below

- can I use drives of different sizes and from different manufacturers together in a single NAS to form a single volume?

Yes, you can do that. However, volume capacity might be changed if you use different sizes HDD in a RAID configuration.
e.g.

[3*2T + 1*3T] in RAID 5, the total capacity will be around 6 TB

- does adding these initial drives work with no manual configuration needed, in other words can I just add a few drives and they all get automatically merged together into a volume where any single drive can fail (Raid 5)? Or how many steps would that take?

With our volume quick setup (you can do this when you initialize the NAS, or create another volume if the NAS has been configured), select what kinds of requirement you like (I would suggest select "Balance", this also fit your requirement), click "Apply", the NAS will merge all the available HDDs together to RAID 5 volume.

For more detail, You can refer to this link below (please refer to section 2)

http://download.asustor.com/college/en/ ... o_RAID.pdf

- can I also expand the whole volume while using it? How does that work in practice, can I just remove my smallest drive and replace it with a bigger drive and the NAS figures out the rest? (If you think that's impossible, that's exactly how the Drobo works). If it's a bit more complicated on an Asustor NAS, can you give me a rough explanation what steps this would take?

We do support online capacity expansion,
here is the instruction that will guide you how to do it (Please refer to section 3)

http://download.asustor.com/college/en/ ... ansion.pdf

- my main beef with the Drobo is that expanding is quite a hassle. Say I want to move from a [4 * 2TB] configuration to a [3 * 2TB + 1 * 3TB] configuration, with 5 TB filled. On the Drobo, cleaning up after the change will take about 5 days, which cannot be interrupted, and during which the fan constantly outputs about 45dB. Hardly ideal for single bedroom apartment How long would this take the Asustor? What would be the average noise during that procedure? And can the task be interrupted and restarted at any time without losing any data?

I have no idea how Drobo work about change RAID configuration, but in our system when you move from a [4*2TB] configuration to a [3*2TB + 1*3TB], there are 4 steps you need to do
1. Back up your data
2. Remove data volume
3. Setup the volume
4. Put the data back

About the average noise, with my experience, most of the noise come from the HDD not the NAS, so it's more important to choose the silence HDD
but let me consult our test department, see if they have any test result for reference.

- is there a maximum range how far I can expand a volume? In other words, can I just start with 2*250GB drives and then do RAID online expansion to expand that to 4*10TB drives (when 10TB drives arrive in four years) - or is there something like "maximum elasticity of 10x the initial size"?

So far we have a 16TB limitation on online volume expansion due to the limitation of linux kernel ( Online expansion capacity can't exceed 16TB)
we are working on this problem at present, see if after upgrade the linux kernel can conquer this.

- can I go smaller? In other words, if I have a 4*4TB setup, filled, then remove all data and just leave 200GB on it, can I then remove two 4TB drives, one after another, then insert 2 250GB drives, then remove the other 2 4TB drives, all while still using the setup? (This is not as important if it doesn't work, but it works on the Drobo and it would still be valuable to know.)

I'm sorry to say in our system you can't do this.

- say I have a setup with 4*4TB drives, and I have done various RAID online expansions in the past to arrive at this setup (for example, [2*250GB] -> [4*1TB] -> [2*1TB + 2*2TB] -> [4*3TB] -> [4*4TB]). How do I recover my data from a theoretical full failure of the NAS itself? Can I just buy another Asustor unit, add the drives into this new unit and all my data automatically appears there? Or how difficult would that be?

We support system migration, that means you can put all your original HDDs to another ASUSTOR, and then boot the NAS up, you will see your data automatically appears.
for more information, you can refer to this link
http://download.asustor.com/college/en/ ... ration.pdf

[Zumi]

Great answers, thank you!

I'm looking forward to those noise test results.

Cheers, Zumi

[Steve@AST]

Hi Zumi,

unfortunately, our test lab does not have the report which similar to the test condition that you wanted.
but they provide me this, maybe you can take it as reference

they put WD HDDs in AS-604T (4 HDDs), and the power the NAS on,
during power on procedure, the noise that we detect is around 24 db

hope this help

br.

Steve