[OpenAFS-devel] Support for huge (really huge!) cell

[Chris Huebsch]

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Hello,

our project[1] continues and we aim to build 1 (one!) AFS-Cell for all
schools in our town. That means 40-50k users, ~15 TB Filespace and
150-200 Servers. And the last number is the problem. The server-machines
will be distributed across the town in app. 100 schools. There will be a
central server-farm for management and primary file- and db-servers.

We expect that our VPN will be stable but not absolutely free of
downtime. So we need some limited "offline" capability.

We will not have abundand bandwith, so we think, that there need to be
AFS-Fileservers in every school, serving the user-volumes of the pupils
of that school.

We also think, that it would be wise to have the RO-Clones of the
filesystem-skeleton (root.afs, root.cell, users, ...) in every school.

I looked at the source and found out: Only 13 RO-clones per volume. This
is by far not enough. Can I change this number to - lets say - 200?
Do the algorithms scale that far? What about the size of the
data-structures? Will I get trouble with RX-Protocol because of too
large packets? I read that there are static arrays using this limit. Is
it possible to change that to a dynamically allocated array?


We plan to install a read-only AFS-DB-Server in every school too (makes
at least 100). Will Ubik scale to this number of Servers?

Klog seems to select its kaservers randomly from the CellServDB - what
about afsd? Is there a "use next"-Server heurestics. What about
school-dependend CellServDB-Files, containing just the
"local"-RO-DB-Servers and the "master"-RW-Servers?

We would be happy to use AFS. To be honest - I do not know any FS
that would be more useable either.

We have some capacity developing patches for OpenAFS, but we need some
hints regarding compatibility and stability.

Thank you for your help, Regards


Chris
[1] Look at http://www.openafs.org/success.html
--=20
Chris Huebsch     www.h=FCbsch-gemacht.de | TU Chemmnitz, Informatik, RNVS
GPG-Encrypted mail welcome! ID:7F2B4DBA |   Str. d. Nationen 62, B204
   Chemnitzer Linux-Tage 2005, 5.-6.M=E4rz |       D-09107 Chemnitz
     http://chemnitzer.linux-tage.de/    |  +49 371 531-1377, Fax -1803
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