[Linux-cluster] Upgrade from 32-bit to 64-bit servers

[Jan Bruvoll]

Rob Kenna wrote:

> This needs some clarification.  GFS 6.1 is capable of supporting
> multiple 16TB filesystems on 32-bit OS architectures and 8EB on 64 bit
> OS architecures.  We are currently supporting multiple 8TB file
> systems and will officially support larger file systems in time.  The
> point is GFS is a 64 bit filesystem, with the same on-disk layout,
> regardless of the CPU architecture of the cluster nodes.
>
> You can also run mixed 32/64 architecures across x86/EM64T/AMD64/ia64.
> Obviously, mixed 32/64 combo's can not exceed 16TB.

Hi,

thanks for the clarification - but I still have the following question:
 - will we be able to take the already existing filesystem, created on a
32-bit node, use it on a 64-bit platform (i.e. upgrade all the nodes),
and from there extend it to whatever size >16Tb we desire, or will we
have to adjust blocksizes, etc. to go past the 32-bit platform limit?

I understand that the filesystem itself, on-disk, is not the part
imposing the limit - however I think I have seen somewhere that one has
to use larger block sizes to reach the upper limits of file system size.
Is this correct?

Thanks again
Jan