I wouldn't say that either AFS or Coda are good choices for hosting
databases, as they are propagate-on-close systems. Databases are always
appending blocks to and modifying blocks in the middle of files. I don't
know about the practical capacity limits of AFS, but CODA would choke on
both gigabytes and terabytes of data. You'll probably be better of using a
storage array from MTI and a fibre-channel SAN.

-M


-----Original Message-----
From: Eric Tan [mailto:eric_at_wizoffice.com]
Sent: Saturday, January 22, 2000 7:55 AM
To: codalist_at_TELEMANN.coda.cs.cmu.edu
Cc: wizsystems_at_wizoffice.com
Subject: Re: CODA Sever with 42G


I've read about AFS, is  it  a better choice as a database solution as
compared
to CODA ? Because we need a filesystem that can hold a few hundres of
gigabytes or terabytes of data. 

Eric


On Thu, 20 Jan 2000, Peter J. Braam wrote:
> It's also worth pointing out that some database servers statically link
> their binaries to remove shared libraries from the "middle" of the address
> space.  This should give you considerably more.
> 
> - Peter -
> 
> 
> On Tue, 18 Jan 2000, Jan Harkes wrote:
> 
> > On Tue, Jan 18, 2000 at 10:37:40AM -0800, Phil Nelson wrote:
> > > 
> > > >I just wish to know what is the optimum configuration I can have on a
> > > >42G Raid drive. I have 256M of RAM and a local SCSI drive of 9G and
> > > >an external RAID of 42 GBHDD. Its a PIII500MMX IBM Box. /vicepa will
> > > >be on the external raid while the rest on the local drive.
> > > > For a 42GHDD , I need about 1.7G of RVM according to the 4% rule and
what
> > > >about the Log size? Does my swap partition plays a part here for the
RVM??
> > > >How much space should I allocate?
> > > >
> > > >With 1.7G of RVM , do I need to run rdsinit instead of
vice-setup-rvm??
> > > 
> > > I haven't heard of a server of this size yet.  Since is is not one of
> > > the standard setups in vice-setup-rvm, you would have to init RVM
yourself.
> > > I did it for a 6G server (also not one of the standard sizes.)
> > > 
> > > A big problem you may have is the startup time with such a large RVM,
IF 
> > > you have enough VM space to map it in the first place.  This can be
helped
> > > by using a relatively new flag, "-mapprivate", for the server.  I
believe
> > > it is in coda 5.3.4, but I'm not sure.
> > 
> > Yes mapprivate is available in the 5.3.4 release. One caveat, it only
> > works when RVM is stored in a file.
> > 
> > You actually need to play with the address where rvm is mapped. We
> > currently map it at 0x20000000. Linux places shared libraries and other
> > memory mapped files at 0x40000000, which limits the usable area for RVM
> > to about 512MB.
> > 
> > By moving the address where RVM is mapped to 0x41000000, you'll put it
> > above the libraries where there is room to 0xbff00000 before you hit the
> > stack. That gives about 2031MB of available space.
> > 
> > Check /proc/`pidof codasrv`/maps to see how the memory map is layed out.
> > 
> > Jan
> >
-- 


  Eric Tan
  WizOffice.com Pte Ltd
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