I am looking at buying one of these with 2 x 4tb drives or 4 x 2tb drives. I am wondering about scalability. If I go with the recommended RAID5 - where can we go from here? If it turns out that we running out of space with a 4 drive array - how do you upgrade - all at once?
With two drives can we just add another pair the same size? On the face of it this sounds more doable and its also the cheaper option, but please let me know if I am wrong. Thanks
No, of course not! One after the other, always let the RAID be recreated. Then, at the end, you can raise the existing RAID to its new capacity.
The new drives, if you start partly populated, shall have at least the same size or bigger as the both inserted.
Thanks. I understand that in a RAID5 array I can replace one disk at the time and rebuild the array, but am wondering that in my situation a better solution would be to get the 4 bay unit, and run two drives in RAID1.
Then in the future if it looks like I need more space then I can get another two and change to RAID 10 mode. Would that be a viable and easy way to double my storage? I know that in 5 mode I get more actual space to use, but there is also the rebuilding issue.
Yes, this is supported too. You start with two drives, then insert another two with same or higher capacity, then you will be asked by the system a) if you want to increase the capacity and b) what type of RAID (10 or 5) shall be created.
But take care that no power cut occurs during this process! Better hook the My Cloud onto a UPS Uninterruptable Power Supply.
Thanks for this. So storage can be added whilst keeping the data intact (as long as power kept on) I see. I think this is something that you guys should talk about in the promotion and manual of the unit because its a question a lot of people have about RAID - coming from a desktop user base people are generally scared of it. Synology make a big deal about how - with their systems you can add to storage easily and people will make purchase decisions based on this. I nearly did!
You say that a larger drive can be added, but I thought that in RAID5 all drives would have to be the same - or at least default to the size of the smallest drive. So for instance if I had two 2tb drives, and later added a pair of 4tb drives, would the system see these as 2tb or 4. And if 4 then how would the extra space be allocated? Important to know, because you say we can upgrade capacity, but as far as I know, once all bays are full and the RAID level decided upon - we cannot then go ahead and change from 5 to 10 for instance without data loss.
If you could provide some examples of what it possible it would be most helpful, to me and many others.
We do: All Products: Shop Hard Drives, SSDs, USBs, & Memory Cards | Western Digital
Disk management:
RAID: JBOD, spanning, 0/1/5 10/5 + hot spare support
RAID migration
JBOD to RAID 1
JBOD to RAID 5
RAID 1 to RAID 5
Hot swapping
Hot spare (in four disk mode)
Disk roaming
Array roaming
Yes, larger drives can be added and Yes, your RAID 5 will have use the smallest drive capacity for all others. But No, you don’t need to have all drives at the same capacity as the smallest one is the trigger for the rest.
But: if you have some capacity left on bigger drives, you can use this capacity for another JBOD or RAID to make use of this capacity. You won’t lose this capacity, you could add it in another array.
Start is 2 x 2 TB in RAID 1
Adding 2 x 4 TB, migrate to RAID 5
Result is an array of 4 x 2 TB in RAID 5
As I wrote above, you could create another array RAID 1 to make use of your capacity of twice 2 TB on the bigger drives. At the end you would have aray1 with 4 x 2 TB and array2 with 2 x 2 TB (or 2 x JBOB each 2 TB).
No, of course not. This would be a rework of an existing RAID array by deleting this array and creating a new one. Remember: RAID 5 is 75% capacity to use, RAID 10 is 50% capapcity. Therefore: a “RAID shrink” is not possible.
This is a so called “RAID growth”. This option is possible by exchanging drives one after the other to higher capacities. Let’s stay in your example:
Your lastest capacity is 4 TB each drive, let’s say in RAID 5.
You could exchange these drives against our lastest ones, the WD Red 8 TB.
After cycling through all bays, you would have an existing RAID 5 with 4 x 4 TB size on 4 x 8 TB drives.
NOW you can start the RAID growth to have a 4 x 8 TB array at the end.
But, again, hook the machine onto an UPS to avoid power cuts. RAID growth is a long lasting process, I expect a RAID growth on 8 TB drives lasting somewhere 48 hours to finish. Within this time, a power cut would be deadly.
That is a great help, thanks very much.
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Hello. I would like to buy My Cloud EX4100 0TB + 4 x WD Red 8TB HDD for use it initially in JBOD mode. But I suspect that might not work because in wdc.com site is declared a maximum capacity of 24 TB. I posed the question to technical support by telephone, and they told me that currently the EX4100 NAS is only guaranteed for a maximum capacity of 24 TB. Can I have your opinion? Thank you
I have just migrated RAID 1 disks from Ex2100 to Ex4100 and the new RAID is working fine. However when I introduce 2 extra disks I get an option to migrate to RAID 5 but only an option to change to RAID 10 and lose all data. Am I missing something, do I need to go to 5 then 10?
All help gratefully received.
I don’t believe the process works as “advertised”. Check out Format or Migrate for details on when I tried to do it. I ended up backing everything up to another NAS and rebuilding it from scratch (including my docker apps).
Cheers,
JediNite
Joerg,
It is all good and well to say it is supported, but there is absolutely nothing in any FAQs, user manuals or other documentation on how to actually do it.
I ran into problems with this a few months ago and instead decided to cut my losses trying to migrate it and just build it from scratch,
Cheers,
JediNite
Are you sure that one can expand an existing RAID5 array from 4 x 4 TB to 4 x 8 TB?
This means expanding an EXT4 volume from 12 TB to 24 TB… which requires resize2fs tools 1.43+.
However the WD software has version 1.42.x …
Did you test this expansion process?
