Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Thursday 23 December 2010 21:24:07 Tim Mauerbach wrote: > 2010/12/23 J. Ryan Earl <oss at jryanearl.us> > > > On Thu, Dec 23, 2010 at 11:23 AM, Tim Mauerbach < > > > > tim.mauerbach at googlemail.com> wrote: > >> I am thinking about the structure of a new mailserver on top of > >> raid1/lvm/xen. > >> > >> Two different approaches come to my mind: > >> > >> 1. One big LV as DRBD backing device for the whole guest (os + data). > >> 2. One small LV without drbd for the base system + one big LV as DRBD > >> backing device only for data (maildirs+mariadb). > >> > >> Is the maintenance overhead of 2 worth the performance gain? > > > > I'd definitely go with 1, and it has nothing to do with performance. If > > you put the whole VM on top of DRBD, and then make that a primary/primary > > (aka active/active) DRBD then you can live-migrate the VM between host > > and/or use Remus VM-mirroring for VM-HA. I don't see why anyone would > > ever go with 2 as leaving the OS unreplicated on the small LV exposes > > you to big potential downtime as you rebuild a new OS for the > > replicated-data in the event of a failure. Am I misinterpreting what > > you mean? > > > > -JR > > Thanks for your input. > You´re right. It has nothing to do with performance, I meant efficiency: > > The idea of 2 is to prevent live-replication of not that important non-user > data (os + tmp|log files) that could be replicated via rsync at midnight. > Thus I could use my DRBD capacity more efficiently and only for important > data, though at the expense of maintainability. > > Best Regards > Tim When you scale your hardware correctly, you can get awesome results with DRBD. I second JR's suggestions. Just out of curiosity: what mailsystem, how many mailboxes and what storage are we talking? b.