[Zope] Will ZEO solve my problem?
Kyler B. Laird
laird@ecn.purdue.edu
Mon, 02 Jul 2001 20:13:11 -0500
On Mon, 2 Jul 2001 15:11:14 -0700 (PDT) you wrote:
>have you looked at Coda or Intermezzo? Both distributed file systems,
>although I've used niether.
I've looked at these for other purposes. They're
pretty complex solutions for such a simple
problem.
Because Data.fs is a transaction log, and thus
only grows by having bits added at the end (except
when packed - certainly an exception that must be
handled), it is ripe for this simple "tail -f"
solution. There is no need to have something
that is good at recognizing changes within a file
or handling all the other filesystem goodies
(like ownership/modes/locks/...).
After talking about it more today, it looks like
we will probably even stream the updates to at
least two machines. One will be off-site in case
things *really* go bad. It will not be used as a
ZEO server, but will only serve to hold the data
in case the other two go bad. (This is
especially important when the primary has already
gone down.) I might even encrypt the outgoing
stream and store it at another location that I do
not administer.
Hmmmm...it shouldn't take much hacking to be able
to specify one "file" as input to Zope and one as
output. That would mean that I could, for
example, write each day's transactions to a
separate file, concatenating all of them any time
I start Zope. This would allow me to easily back
the database out a day (as I did recently) or
stream only updates to another server. (I could
even compress the input files.)
--kyler