NAS326 maximum volume size

mikewest9102

Hi, I've read the NAS326 spec sheet but couldn't find the answer to my question, what is the technical reason for the "16TB maximum volume size" exactly?


I have several 18TB drives here (ST18000NM000J) that I would like to use in the NAS326 in a RAID-1 as backup solution, however the storage manager says that 16TB per drive is the limit.
Why is it not possible to address the entire 18TB? As far as I know ext4 shouldn't have any issues with supporting that.

Mijzelf

For some reason the ext4 64bits mode is not supported, which means the filesystem size is limited to 2^32 * 4KiB (blocksize) which is 16TiB, or 17.6TB. So if you use 18TB disk, around 400GB will not be used.

@MarkusDesk has a valid point, yet I don't know how valid. AFAIK there are 2 threads about the issue in this forum. Anyway, it can be solved by installing Debian on that box. That also solves the 16TiB limit.

MarkusDesk

Hi,

As you are planning to use some large hard drives, even if you get the 18TB drives working, I think it will be risky. The NAS326 has a bug that corrupts your data silently and Zyxel support told me they will not be fixing it as the product is at end of life. Just imagine 18TB of corrupt data!!

Mijzelf

For some reason the ext4 64bits mode is not supported, which means the filesystem size is limited to 2^32 * 4KiB (blocksize) which is 16TiB, or 17.6TB. So if you use 18TB disk, around 400GB will not be used.

@MarkusDesk has a valid point, yet I don't know how valid. AFAIK there are 2 threads about the issue in this forum. Anyway, it can be solved by installing Debian on that box. That also solves the 16TiB limit.

mikewest9102

MarkusDesk said:

Hi,

As you are planning to use some large hard drives, even if you get the 18TB drives working, I think it will be risky. The NAS326 has a bug that corrupts your data silently and Zyxel support told me they will not be fixing it as the product is at end of life. Just imagine 18TB of corrupt data!!

 The data corruption bug sounds rather serious, I did not know about that, thanks for letting me know!

Mijzelf said:

For some reason the ext4 64bits mode is not supported, which means the filesystem size is limited to 2^32 * 4KiB (blocksize) which is 16TiB, or 17.6TB. So if you use 18TB disk, around 400GB will not be used.

@MarkusDesk has a valid point, yet I don't know how valid. AFAIK there are 2 threads about the issue in this forum. Anyway, it can be solved by installing Debian on that box. That also solves the 16TiB limit.

I've tried it myself and you're completely right. This is a real bummer, a RAID-1 18TB backup box would've been neat (but that plan is already spoiled by the data corruption issue). Here's the drive connected via SMB in Win10.

I'll definitely try the Debian solution, in fact I was considering an alternative OS but was still clinging to that default setup for the sake of it because I wanted to use it "as is" or "as intended by manufacturer", but oh well, why not try something new.

Thanks you both for your answers, very helpful.