RE: 2-tape drive testing

["Douglas Olson" <dlolson@lbl.gov>]

I think that the COS is determined when the file is first
put into hpss.  Subsequent reads out of hpss will always
use that COS.  This is independent of the pathname.
I don't see how it affects the CM.

Doug

> -----Original Message-----
> From: David M. Malon [mailto:malon@anl.gov]
> Sent: Thursday, October 01, 1998 8:40 AM
> To: dlolson@lbl.gov; gcdev@sseos.lbl.gov
> Cc: malon@anl.gov
> Subject: Re: 2-tape drive testing
> 
> 
> >  
> >  I was thinking a little more about the 2-tape drive issue.
> >  Rather than arange to have 2 drives put into one class
> >  of service so that an individual tape may go into either
> >  drive, what about just spreading files over 2 existing
> >  classes of service.  When we retrieve them, a given file
> >  will always go to the same tape drive, but we will
> >  know that the files are spread across at least 2 tapes.
> >  We can also do this without a reconfiguration of hpss.
> >  
> >  Doug
> >  
> 
>    Wouldn't this imply that Luis would need to know the class of 
>    service, rather than just the HPSS path, for every file?  I 
> know he uses 
>    setcos with a fixed number in his pftp scripts now.  If Luis 
>    needs to write code to accommodate this approach, it becomes a 
> matter of 
>    resources and time (GCA effort vs RCF effort?); I think Luis is also 
>    working on a couple of other issues (we've been running with 
> cmanager.old, 
>    for example).  
> 
>    Luis, what would implementing Doug's suggestion require on your part?
> 
>    Perhaps this is something we should discuss at the GCA phone meeting.
> 
>    David
> 
>