[Linux-cluster] replication

[Mustafa A. Hashmi]

On 7/7/06, Kovacs, Corey J. <cjk at techma.com> wrote:
> Is there a specific reason you need to avoid shared storage? If there is,
> then
> you might look at Lustre which uses a bunch of host computers (OST's) as
> storage engines and makes the files available to a single namespace. To be
> really useful you need lots of OST's which are not consumers of the
> filesystem.
> The benefit is that you can add capacity and throughput by simply adding
> OST's.
> The bad thing is that there is no built in redundancy of OST's. They can be
> made to be redundant by using other clustering technologies (such as RHCS)
> but
> for now, the OST's are not, by nature redundant. In the next year or so, they
>
> expect to be able to configure OST's as raid-1 and raid-5 personalities but
> it
> no where near that yet (raid-0 now).

True, however, failover for OSS require OST come from shared storage,
or, if using local drives on server, you want to replicate (drbd) and
integrate with linux-ha and a stonith device.

Active/active or active/passive scenarios can both be easily designed
-- given hardware, etc.
-- 
Mustafa A. Hashmi
mahashmi at gmail.com
mh at stderr.net