Re: How do I make every node have direct access to the file system?

On Tue, May 12, 2009 at 06:18:25AM -0700, CooLCaT@Vienna wrote:
> 
> hi!
> 
> thirst of all i must thank you all for your postings.
> 
> let's begin from the start:
> 
> i have a running master node with 2 partitions
> 
> /dev/sda1 mounted as /boot
> /dev/sda2 mounted as /
> 
> let's forget about swap partition for now
> 
> there are howtos for mirroring /dev/sda2 with the help of drbd to another
> node

Right.

> if the master node goes done then the other takes over, as far as i
> understood the whole thing.
> i havent had time yet to play with the drbd solution.

Thats the scope of drbd.

> but what happends if the second node goes also down?
> the cluster becomes unavailable.

Right.

> so we thought of using a nfs share instead of /dev/sda2
> 
> so the master node boots up and instead of using /dev/sda2 as / filesystem
> it uses a
> nfs share. the next node boots from it's hard disk, finds the masternode an
> continues as usual
> 
> we tought of using openfiler as nfs server, because openfiler includes also
> failover to a second
> openfiler installation.

Hm. Lets see: you do not trust your 2 openSSI-master nodes, so you want
a solution, where every node of your cluster could take over the master
role, and you rely therefore on a 2-node-fileserver for the root file
system?
Is your openfiler file server so much more reliable than your 2 openSSI
master nodes?
Maybe it could be cheeper to invest the money for the openfiler-system
into some more reliable HW for your OpenSSI-nodes???

What are your requirements (in uptime, costs, etc) for your system?
What is the probability for a failure of your 2 openSSi master nodes
_at_the_same_time_? (Because I guess, if one server fails, then you will
nearly immediately repair or substitute your failed server ...)


> the goal is, that every node can become a failover node, not even only two
> nodes which are mirrored via drbd.

Relying on a (only) two node file server ;-))


Regards, Robert
(PS: I am not really an expert, but if you like, then we could discuss
this stuff also privately in german ...)


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