Cheap VM cluster (software, storage) ideas

[Ghiora Drori]

Hi,
Amazon EC2 instances plus their EBS disks.
Scalable, available, reliable (from my experience) and you can experiment
for a few $'s a day.


On Wed, Mar 4, 2009 at 11:06 AM, Ira Abramov <Lists-Linux-IL at ira.abramov.org
> wrote:

> related to the Citrix-vs-VMware question, in the spirit of the times...
>
> I want to create a way to host a cheap HA solution for a web hosting
> outfit. they are running a few pretty busy asymetric servers and want to
> start improving that infrastructure. each machine holds several dozens
> of virtual hosts.
>
> At the moment each server has its own local storage and mysql. every
> part is a SPOF other than the minimal RAID and such things.
>
> I'm thinking:
> * Move to a central non-virtual MySQL for the backend.
> * have two servers go P2V and have those VMs hosted back on their
> original hardwares (sadly this means some painful downtime), and find a
> way to let them crash-migrate for HA (still trying to figure this out)
> * Second stage, add a second MySQL in a master-master setup.
>
> I'd love to have two servers with symetrical setup, but as you can
> guess, the virtual hots are dozens of different apps that are too
> expensive to go and rewrite for clusters at this point, with the issues
> of user-uploaded files having to be available to both Apaches, etc.
>
> Assuming we want the cheapest reliable solution, i.e. not a $6K-20K SAN
> and FC, I am looking for an easier solution (easier on the pocket at
> least). However NFS proved to be a disaster in such cases (high-load web
> services), OCFS has not been nice to me with any setup other than maybe
> Oracle clusters, and GFS also never ran smoothly in my tests.
>
> Also OCFS and GFS require a common disk, which at this budget would be a
> Linux machine running an iSCSI target at best (or OpenNAS).
>
> Am I missing something? Can this kind of reliability be achieved without
> shelling out big bucks?
>
> Of course, The other option is just separate the MySQL, have a third
> machine rsync the files of the two (non virtual) servers every few
> minutes and have the hosting farm's layer4 switch redirect to the
> fallback if something happens. Not very "smart" nor scalable, but does
> 70% of what we need till a bigger investment is required.
>
> your thoughts, as before, are welcome...
>
> Thanks,
> Ira.
>
> --
> Can't catch me yet
> Ira Abramov
> http://ira.abramov.org/email/
>
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>



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