[YLUG] Server purchase

[James Carter]

On Fri, 2006-05-19 at 11:14 +0100, Richard G. Clegg wrote:
>  I've had a brief scout and the hardware RAID I could see 
> involved stupidly expensive SCSI disks -- is this unavoidable?

adaptec do a range of SATA RAID hardware that work well with linux.
we're talking adaptec here, so the cards aren't particularly cheap, but
they are reliable and you can use inexpensive SATA discs. i agree with
the higher end SCSI discs, it should ready be called RAED! :)

> 
> 2) The idea at the moment seems to be to have two machines, a main 
> machine and a backup and to use a virtual IP address, IP chains and 
> heartbeat to get the machines to switch over on failure.  The mysql 
> database will be mirrored (we've set that up before) and I guess there 
> are other things we might need.  There is also a daily backup to another 
> machine at a geographically remote location (in case of fire/theft of 
> our main servers).  Does this seem a reasonable set up?  Anything I need 
> to think about?

this is a similar set up to what we use for failover here in CS. one
potential issue to look out for is that some routers take a long time
(hours) to notice IP failover making the failover useless for clients
outside of the subnet. we implemented MAC address failover to work
around this (which gives you faster failover times anyway). it's easy
enough to do if you have a spare ethernet interface for the virtual
address. we've managed to do it with a single ethernet card too, but
that's a bit more of a challenge. :-)


-- 
James F. Carter, Senior Experimental Officer (Software)