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[COLD] 1 sec backups

daemon@ATHENA.MIT.EDU (Thu Jun 13 13:39:06 1996 )

Date: Thu, 13 Jun 1996 19:06:10 +0200
From: silovic@srce.hr (Miroslav Silovic)
To: coldstuff@cold.org

In respond to the previous message (I lost the quote, sorry):

In tuning the Cold server, I'm looking forward to 100-200 users online,
and even 1000 is not out of consideration. Let's see what happens with
1000 user backup.

I expect that many people would require about 5000 objects in the object
cache, about 4000 of which would be marked as modified at any given
time. So, it's 4000 objects times 3kb/object (average). Remember, Cold
doesn't decompile the methods before saving, and that is the main
time-issue with MOOs.

So, we have 12MB disk access. On a fast machine (and you *really* want a
fast thing for 1000 users), it's 15-20 seconds (while the 100+ MB
database copy would take far longer, in the background. Users wouldn't
notice that unless the RAM cache fills up with modified objects, in
which case the game would pause further till the filesystem backup is

Mind you, with 100 users, we're in the order of magnitude of 1 sec for
backup, so it's not *too* optimistic. :) Many MUSHes spend only a few secs
for it.