Re: who uses Lustre in production with virtual machines?

[Todd Denniston <Todd.Denniston@xxxxxxxxxxxxxxxxxxxxx>]

Emmanuel Noobadmin wrote, On 08/04/2010 11:33 AM:
> Easier because instead of running gluster raid 0 on top of DRBD raid
> 1, we can take out the DRBD layer and just use gluster to achieve the
> equivalent by distribute on replicate.
> 
> More importantly there is the issue of cost, DRBD needs a pair of
> server per node for active-active. However, gluster allows me to get
> RAID "0.67" redundancy by "round robin" replicate.
> 

I missed this.

> i.e. If every storage node has 2 mdraid 1 block devices md0 and md1, I
> can mirror Server1 md0 to Server2 md1, Server2 md0 to Server3 md1 and
> so forth. Theoretically capable of surviving up to 50% node failure if
> no two adjacent node fails together. This for the cost of N+1 as
> compared to DRBD's Nx2 cost.

DRBD cost would still be N+1, not Nx2, if setup similarly, I think.

If Gluster is doing the mirror of "Server1 md0 to Server2..." by itself, then yes adding DRBD to it
would be a bit overkill, as I would be having DRBD setup to do something similar.

-- 
Todd Denniston
Crane Division, Naval Surface Warfare Center (NSWC Crane)
Harnessing the Power of Technology for the Warfighter
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