[SAC] DRBD on the new servers or not?

Alex Mandel tech_dev at wildintellect.com
Sat Mar 27 16:02:34 EDT 2010


DRBD is software that basically behaves like a raid 1 (mirror) on a
virtual machine. The advantage I've been told is failover redundancy and
the ability to apply updates without downtime(you apply to the mirror
and then swap). The disadvantages are that it takes exactly double the
disk space, and potentially leads to slower I/O on the disk because it
has to wait until it finishes writing to 2 places (possibly on 2 machines).
Here's the info on the software:http://www.drbd.org/

OSL has offered this feature on a per vm basis meaning we can choose to
have it on or not for each particular vm.

For Backup the decision was easy to say no. But for the Other VMs the
decision is a little trickier as the HD sizes are small and 100% uptime
might be good for some services.

I'll let Martin who seems to have used it before comment some more.

Unless I'm told otherwise here's the current plan:
http://wiki.osgeo.org/wiki/Infrastructure_Transition_Plan_2010#Final_Plan

We need to finish installing the Base image and make a decision about
DRBD for Wiki and Secure before monday so OSL can go ahead and create
those VMs for us. In the future we will have access and instructions to
build VMs ourselves, the first batch is being done by OSL so they can
test the instructions.

Thanks,
Alex


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