I'm wondering if virtualization could be used as a cheap redundancy
solution for situations which can tolerate a certain amount of
downtime.
Current recommendations is to run some kind of replication server such
as DRBD. The problem here is cost if there are more than one server
(or servers running on different OS) to be backed up. I'd basically
need to tell my client they need to buy say 2X machines instead of
just X. Not really attractive :D
So I'm wondering if it would be a good, or likely stupid idea, to run
X CentOS machines with VMware. Each running a single instance of
CentOS and in at least one case of Windows for MSSQL.
So if any of the machines physically fails for whatever reasons not
related to disk. I'll just transfer the disk to one of the surviving
server or a cold standby and have things running again within say
30~60 minutes needed to check the filesystem, then mount and copy the
image.
I thought I could also rsync the images so that Server 1 backs up
Server 2 image file and Server 2 backs up Server 3 etc in a round
robin fashion to make this even faster. But reading up indicates that
rsync would attempt to mirror the whole 60gb or 80gb image on any
change. Bad idea.
So while this is not real time HA but in most situations, they can
tolerate an hour's downtime. The cost of the "redundancy" also stays
constant no matter how many servers are added to the operation.
Any comments on this or is it like just plain stupid because there are
better options that are equally cost effective?
_______________________________________________
CentOS mailing list
CentOS@xxxxxxxxxx
http://lists.centos.org/mailman/listinfo/centos
