From time to time we get asked things like this:
I want to use a 10TiB volume with DRBD, is that supported”?
The easiest way to answer things like that is to say look for yourself on the public DRBD usage page – the biggest public device size is ~220TiB, so go figure 
The current maximum device size is 1EiB (1 ExiByte = 1024 PetiByte, 1 PetiByte = 1024 TibiByte1), so there’s a bit of room left.
DRBD needs about 32MiB RAM per TiB storage; so for 1PiB storage you are at 32GiB, and for 1 EiB storage at 32TiB of RAM just for the DRBD bitmap2. Having a bit more for the OS, userspace and buffer cache is left as an exercise for the reader.
If you’ve got questions, ask the DRBD experts at LINBIT – we wrote the code, after all!
I google from http://en.wikipedia.org/wiki/Terabyte
1TebiByte = 2^40
1Pebibyte = 2^50
1Exbibyte = 2^60
You memtioned that 1EiB (1 ExiByte = 1024 TibiByte1).
But I am confused.
If TibiByte means TebiByte, 1024TibiByte should be 1Pebibyte.
Oh yes, thank you very much, that was an error.
I’ve fixed the article.