[CentOS] Clustering

Thu Feb 4 23:34:02 UTC 2010
Les Mikesell <lesmikesell at gmail.com>

On 2/4/2010 3:17 PM, Bo Lynch wrote:
>
> Right know we have about 30 or so linux servers scattered through out or
> district. Was looking at ways of consolidating and some sort of redundancy
> would be nice.
> Will clustering not work with certain apps? We have a couple mysql dbases,
> oracle database, smb shares, nfs, email, and web servers.

Each app has it's own best way to provide the redundancy and 
auto-failover and it's own set of tradeoffs of the added complexity vs. 
the possible reduced downtime if the primary fails.

I'd balance the options against the low-tech method of having raid 
mirrors in swappable bays with a spare similar server chassis or two 
around plus regular backups kept at a different location.  The raid lets 
you continue in the likely event of a disk failure so you can repair it 
at a convenient time.  Other failures (motherboard, power supply) are 
less likely but can be handled by swapping the drives into an alternate 
chassis (and with Centos you'll need to re-assign the IP addresses that 
are tied to the old NIC mac addresses) with a small amount of downtime. 
  And the backups cover things like operator or software errors (that 
would wipe a cluster too) or a building-level disaster that destroys the 
disks or the primary and spare chassis at the same time.  Some apps may 
be worth the effort to do better.

-- 
   Les Mikesell
    lesmikesell at gmail.com