RAID 5 different drive sizes

My Cloud OS 3 Personal & Network Attached Storage My Cloud EX4
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Hi,

Apologies if this has already been answered elsewhere but I couldn’t find anything on the exact subject.

Recently bought my WD My Cloud EX4, and currently have 1x 4TB, 1x 2TB and 2x 1TB drives that I plan to deploy as RAID 5. I want to eventually replace all the smaller HDDs with 4TB drives.

My question is, once the array has 4x 4TB drives, will it automatically go up to 16GB? Or will it stay at 4TB (determined by the 2 smallest HDDs when the RAID was first created)?

Thanks

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standard rule of thumb would be that it would remain its original size and you would have to transfer the data else where and reimage or rebuild those drives and bring the data back down now that is not a recommended idea because 1 - you would need another storage device to put data into 2 - it would take a long time to rebuild your raid everytime you swap out 1 of the drives in my opinion, there are 2 options 1 - purchase another nas with bigger storage that you want to upgrade to and transfer your data 2 - transfer your data to USB 3.0 external drives now, and take out those 4 drives, and install 4 new ones and transfer data back and not worry about rebuilding the raid on the old 4 drives.

1 Like
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Gigawatt wrote:

Hi,

 

Apologies if this has already been answered elsewhere but I couldn’t find anything on the exact subject.

Recently bought my WD My Cloud EX4, and currently have 1x 4TB, 1x 2TB and 2x 1TB drives that I plan to deploy as RAID 5. I want to eventually replace all the smaller HDDs with 4TB drives.

 

My question is, once the array has 4x 4TB drives, will it automatically go up to 16GB? Or will it stay at 4TB (determined by the 2 smallest HDDs when the RAID was first created)?

 

Thanks

First of all, you need drives of the same size or everything will default to a build that’s based on the smallest drive.  So, your 4TB + 2TB + 2TB will equal 2 + 2 + 2 TBs.  If you want to make the most of the space, you can use JBOD and you will have 4 + 2 + 2 TBs of space.  But you won’t have the reduncancy.

I forgot to add…

To your question, if you replace the 2 - 2TB drives with 4TB drives, you will need to rebuild the RAID to get the expanded capacity of the drives.

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Well technically it would end up being 3TB of useable space (4TB -1TB for redundancy) since my 2 smallest drives are 1TB. 

I read somewhere that the Synergy NAS has hybrid RAID where unused space is reserved for future expansion and I was wondering if WD had something similar

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Not without rebuilding the raid.