Maximum disk sizes

For the NV+ & Duo (and other sparc-based units), it's currently 2 TB. For the Ultra/Pro x86-based units, it's 3 TB. The primary reason is that the sparc-based units only support MBR disks, while the newer Ultra & Pro units support GPT. Not sure if the sparc units will ever support GPT, as Debian has ceased development on sparc-based platforms.

You can read up on the GPT vs. MBR issue here: http://www.burnedin.com/article/gpt-vs-mbr-explained

At the beginning of every hard drive there is a designated portion called the MBR (Master Boot Record). The MBR gives your system information about the drive and if/where to run your installed operating systems. Some of this information reveals details about the size and partitions on the drive. It's a method that has worked well for years, but the MBR is starting to become outdated since it can only hold enough information to define partitions on drives less than 2.2TB in size. This is where GPT steps in. As it turns out, GPT is becoming an option out of necessity because of those size limitations of the MBR. Currently we are on the cusp of regularly pumping out hard drives larger than 2TB and we need this new partition format option so that users can use every bit of space on their huge drives. Basically, GPT reserves a portion of the hard drive, in addition to the part reserved for the MBR. GPT uses this extra space to store even more information about the hard drive and its partitions. This allows for hard drive sizes of ridiculous proportions. How large? Try 9.4ZB, or Zeta-bytes,which (if you're nerdy and really care) is 20 zeros after the "94." Basically, hard drives will be non-existent by the time we need storage that large.

Thanks for the reply...but why do the x86 based units only support 3TB given the explanation you posted?

Webagents wrote:
Thanks for the reply...but why do the x86 based units only support 3TB given the explanation you posted?

Have a look at this thread for details: viewtopic.php?f=17&t=51748#p294048

Webagents wrote:
Thanks for the reply...but why do the x86 based units only support 3TB given the explanation you posted?

3tb drives are the largest available currently.

Suffice to say, x86 devices should support any standard hard drive 3tb (or higher) with gpt support.

Since there aren't any >3tb drives, its hard to say what the future will hold.

Oops, sorry about my previous post. I *thought* you were asking about why the sparc-based units wouldn't support >2TB. Clearly, I answered a question you didn't ask! :oops:

TeknoJnky, as usual, is much better at reading than I and answered the way I should have --- 3 TB is the limit because that's the current max.

Thanks for the replies.


I want to buy a 4 disk nas to add to my duo

I can't justify the £400 Ultra but can the £200 NV+

The disk size limitation worries me a little, but I'm not averse to upgrading later to an Ultra.

See other thread.... Why go through the "pain" of an NV+ ? Do yourself a favour, raise the additional cash & go for the x86 range....

rolski wrote:
See other thread.... Why go through the "pain" of an NV+ ? Do yourself a favour, raise the additional cash & go for the x86 range....

Do you have a link to the thread you mean, looks interesting...

(I did search but couldn't find a thread with that title)

See your thread: http://www.readynas.com/forum/viewtopic.php?f=20&t=55320

The NV+ has the same CPU and memory as the Duo so it'll have pretty much the same performance. You're better off saving some more bucks and getting an Ultra imo, but if you're fine with the 2TB hard drive limit and the performance then go for it.