[DRBD-user] DRBD Question
Diego Julian Remolina
diego.remolina at ibb.gatech.edu
Tue Jan 9 14:33:55 CET 2007
> works fine. in principle.
> still I recommend to NOT use such a setup, because:
> if one box cannot take the full load on its own,
> the failover cluster is useless:
However, I can argue that if one machine can take the load, then it would be a waste of money to
have two machines and one of them there sitting all the time doing nothing, just waiting.
I do not currently have an active/active setup, but have DRBD 0.7.x running on two machines with two
drbd partitions. One machine is mail master (sendmail+mimedefang+spamassassin+clamav+cyrus-imap) and
the other machine is web master (apache+php+mysql). Since we do not get that much traffic in our web
server and mail server, I am sure one machine would be able to take both loads simultaneously and
have lots of power to spare. They are very decent machines hardware wise (Dual Opteron 270 with 4GB
Ram, Areca SATA raid controllers in RAID 10 and Gbit links to our campus network).
> once you need it because one node crashes,
> the other is not capable of taking the load,
> and you are offline anyways.
> even if you think it could take the load, and would just not perform
> "as good as" when having it distributed: your workload will increase,
> and you won't notice when a single machine is no longer capable of
> taking it all, until it is too late.
> I'd recommend to have one node doing all the work.
> but do scheduled switchovers every now and then to reveal
> upcoming hardware problems early, as well as to have a
> convenient way to deploy software, security and bug fixes
> and system upgrades.
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