NFS Filesystem Size Limit?

NFS Filesystem Size Limit?

[Justin Piszcz]

I have a question I could not quickly find on Google/mailing lists--

Say I have some sort of global filesystem or NFS which is 200TB.

Is there a limit either:

A) In the Linux kernel
or
B) In the NFS spec

That would limit the client as to what it could see via NFS or global 
filesystem?

Or could both 2.4 and 2.6 kernels 'see' the 200TB global filesystem over 
NFS or global filesystem?

Justin.

Re: NFS Filesystem Size Limit?

[Trond Myklebust]

On Mon, 2006-12-18 at 14:21 -0500, Justin Piszcz wrote:
> I have a question I could not quickly find on Google/mailing lists--
> 
> Say I have some sort of global filesystem or NFS which is 200TB.
> 
> Is there a limit either:
> 
> A) In the Linux kernel
> or
> B) In the NFS spec
> 
> That would limit the client as to what it could see via NFS or global 
> filesystem?

No.

> Or could both 2.4 and 2.6 kernels 'see' the 200TB global filesystem over 
> NFS or global filesystem?

'df' may or may not report the filesystem size correctly (depends on
whether you have VFS support for 64-bit filesystems enabled, and whether
or not you are using NFSv3 or above), but you should be able to store
200TB worth or data on it irrespective of that.

The one thing that may be limited is the size of individual files. The
NFSv2 protocol limits file sizes to 2GB, whereas NFSv3 and v4 should
allow you to read and write full 64-bit sized files.
Note though, that on most 32-bit hardware, the Linux VM design limits
you to 44-bit file sizes (due to the 32-bit page table + 4k page size).

Cheers
  Trond

Re: NFS Filesystem Size Limit?

[Justin Piszcz]

Thanks for the info!

On Mon, 18 Dec 2006, Trond Myklebust wrote:

> On Mon, 2006-12-18 at 14:21 -0500, Justin Piszcz wrote:
> > I have a question I could not quickly find on Google/mailing lists--
> > 
> > Say I have some sort of global filesystem or NFS which is 200TB.
> > 
> > Is there a limit either:
> > 
> > A) In the Linux kernel
> > or
> > B) In the NFS spec
> > 
> > That would limit the client as to what it could see via NFS or global 
> > filesystem?
> 
> No.
> 
> > Or could both 2.4 and 2.6 kernels 'see' the 200TB global filesystem over 
> > NFS or global filesystem?
> 
> 'df' may or may not report the filesystem size correctly (depends on
> whether you have VFS support for 64-bit filesystems enabled, and whether
> or not you are using NFSv3 or above), but you should be able to store
> 200TB worth or data on it irrespective of that.
> 
> The one thing that may be limited is the size of individual files. The
> NFSv2 protocol limits file sizes to 2GB, whereas NFSv3 and v4 should
> allow you to read and write full 64-bit sized files.
> Note though, that on most 32-bit hardware, the Linux VM design limits
> you to 44-bit file sizes (due to the 32-bit page table + 4k page size).
> 
> Cheers
>   Trond
>