[OpenAFS] tapeconfig capacity parameter still limited to 2TB?

[Charles (Chas) Williams]

butc actually uses a signed int32 so the tape capacity could be doubled
to 4TB fairly easily (I have misplaced the patch somewhere but I could
find it).  That isn't quite 6.25TB but your compression ratio seems
"optimistic" so it might be enough until the next generation of LTO.

https://lists.openafs.org/pipermail/openafs-info/2013-May/039580.html

On Mon, 2015-05-18 at 13:26 -0400, Jeffrey Altman wrote:
> Russ,
> 
> All of the backup protocol messages are limited to sizes that max out at
> 2TB (2^32 1KB blocks).
> 
> I am not aware of anyone that is actively maintaining the backup suite
> shipped with OpenAFS.
> 
> I recommend that the University of Pittsburgh communicate with its
> commercial support provider to request an estimate for designing,
> implementing, and testing the necessary changes.  Changes to the backup
> suite protocols do not require submission through a standardization
> process (unlike other AFS3 RPC suites).
> 
> Jeffrey Altman
> 
> 
> 
> 
> On 5/18/2015 12:48 PM, Howard Jr, Russell A wrote:
> > Over the summer, we are upgrading our tape library from LTO-4 to LTO-6
> > and would like to take advantage of the full capacity of the new tapes.
> > 
> >  
> > 
> > The tapeconfig documentation indicates that the max tape size supported
> > is 2TB.  Is this still the case?
> > 
> >  
> > 
> > Our current drive is LTO-4 with a native uncompressed capacity of 800 GB
> > and a compressed capacity of 1.6TB.  For our current backups, we
> > specified the tape capacity in the tapeconfig file as 1600G.  This has
> > allowed us to utilize the full capacity of the LTO-4 tapes.  Our new
> > tape drive will have a native uncompressed capacity of 2.5TB and a
> > compressed capacity of 6.25TB.
> > 
> >  
> > 
> > If the 2TB limit is still in place, we would like to request that it be
> > increased to at least 6.25TB (or larger to support future tape capacity
> > increases).  Once our new tape drive arrives, we are willing to test any
> > patches to help facilitate an increase in the tape size limit.
> > 
> >  
> > 
> > --
> > 
> > Russ Howard
> > 
> > Systems/Programmer III
> > 
> > Computer Science Department
> > 
> > University of Pittsburgh
> > 
> > 6209 Sennott Square
> > 
> > 412-624-8834
> > 
> >  
> > 
>