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On 2000-11-21T19:19:03,
huatao <thua@xxxxxxxxxxxxxxx> said:
> So if i have dynamic webserver content, the realservers will share one
> database or they each have one and keep them snychro? If those
> requests are mostly database related, i guess the workload will not be
> balanced very well if there is only one database. And if those
> realsevers each have a database, let's say MySQL, is it possible to
> keep them synchro?
Having a single database server in the back would be the most common setup in
this case.
Of course, if your database is the bottleneck instead of the
application/webservers, this won't help much ;-)
Synchronising multiple instances of the same database is rather difficult if
your database doesn't support it: You would need online replication for Oracle
for example.
If your database only changes once per day or so, you could use rsync to
replicate read-only copies of it to each real server after an update.
Even if you would still use a single server to keep the per user data, this
would replicate the bulk of the queries (your database content) and ease the
load on your database server considerably.
> Sorry, i think i did not make myself very clear in last letter, but
> your answer is very helpful, i can learn a lot from it as well :-)
> What i really wanted to say is how to verify those scheduling
> algorithms like rr,wrr,lc,wlc, using browser? But cache is a big
> problem when making verifications.
You can verify this using the logfiles on the real servers.
You can also just have a "hidden" document at a specific location on your real
servers with different content on each node and see whether reloading that
document gives roughly the result you expect.
Sincerely,
Lars Marowsky-Brée <lmb@xxxxxxx>
Development HA
--
Perfection is our goal, excellence will be tolerated. -- J. Yahl
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