upgrades for applications that maintain state - since a user might
have a session created using a new-code box, then hit an old-code box
on the next page view. it takes us many minutes to work through
restarting the entire array.
were you ever concerned about something like that?
I
I'm looking at how to best avoid downtime during a code upgrade, as we often
do spot releases of critical code fixes and we're getting to the usage level
that I don't want to interrupt service to deploy that code. At the same
time, I want to avoid running 200 stat()'s per request for all of the
Gordon Henriksen wrote:
I'm looking at how to best avoid downtime during a code upgrade, as we often
do spot releases of critical code fixes and we're getting to the usage level
that I don't want to interrupt service to deploy that code. At the same
time, I want to avoid running 200
Gordon Henriksen wrote:
I see three options open to me:
1. static mod_perl w/ PerlFreshRestart
Reloads %INC.
downside: Heresay claims historical instablity.
2. dynamic mod_perl
Tears down cleans up Perl interpreter on graceful restart.
downside: Heresay
The best way I've found to deal with this problem is to have multiple
servers behind a load-balancer and do a rolling restart. If you have
servers A and B, you take A out of the load balancer temporarilly,
upgrade it, add it back in, take B out, upgrade it, add it back in.
Using this
Geoffrey Young wrote:
we do that frequently here - 7 servers behind a BigIP. I've always
wondered, though, whether this approach is foolproof for major
upgrades for applications that maintain state - since a user might
have a session created using a new-code box, then hit an old-code box
on
We had been using Option 1 for a long time we had
absolutely no problems (with
mod_perl-1.19/Apache-1.3.14/Perl-5.005).
However on upgrading to mod_perl-1.26, we were getting
hell lot of errors. I have tracked this to a bug in
perl_util.c on fixing this PerlFreshRestart works
w/o any problems.
We had been using Option 1 for a long time we had
absolutely no problems
But doesn't it totally wreck your shared memory? For me that would make
it unusable. I usually get a pretty large percentage of memory to be
shared and count on that for getting maximum capacity from each box.
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