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

[Charles (Chas) Williams]

You can take a look at it here:

http://gerrit.openafs.org/11871

On Mon, 2015-05-18 at 20:56 +0000, Howard Jr, Russell A wrote:
> Charles,
> 
> We'd be glad to test the patch if you can find it.
> 
> Thanks.
> 
> --
> Russ
> 
> -----Original Message-----
> From: Charles (Chas) Williams [mailto:3chas3@gmail.com] 
> Sent: Monday, May 18, 2015 4:28 PM
> To: Jeffrey Altman
> Cc: Howard Jr, Russell A; openafs-info@openafs.org
> Subject: Re: [OpenAFS] tapeconfig capacity parameter still limited to 2TB?
> 
> 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
> > > 
> > >  
> > > 
> > 
> 
>