[DRBD-user] Questions

[Helmut Wollmersdorfer]

crisen at tiscali.co.uk schrieb:

> Configuration: PDC and BDC running on SuSE 9.1 Prof on x86; PDC with 2 drives
> on hardware raid 1, 4 100 Mbit cards (2 on crossover, 2 on LAN); 120 GB
> drives; BDC on simpler config (no raid).The machines will be running Samba
> 3, DHCP, DNS, HTTP and FTP intranet (not externally exposed), email and
> print servers, etc. The idea is to totally replace a W2K server.

> Q: Will drdb work on the SuSE 2.6x kernel? I can't find reference to this
> on SuSE's pages.

http://www.suse.com/us/private/products/suse_linux/prof/packages_professional/drbd.html

Suse supports DRBD 0.7.x, and 0.7.x needs Kernel 2.4.x or 2.6.x. But the 
one and the other Lars can tell you more than I.

> Q: Does drdb support the above services? I.e. should the PDB fail would
> the BDC takeover all of these roles, for example allowing user logins, enabling
> samba shares and IP address serving?

DRBD is a block device. You can use it for (nearly) everything like a 
partition of your harddisk. For failover of services, related 
DRBD-resources and related IP you need something like heartbeat.

> Q: If so, in what order should I do things: First build an entire machine
> and then install and run drdb, or install the OS first with the drdb and
> then the rest?

Install everything first, reserve enough disk space for DRBD-partitions. 
  Then make the partitions, configure DRBD, then configure the services.

> Q: What should I mirror? Can I mirror the whole drive? 

No.

> In one of the FAQ
> (http://lists.linbit.com/pipermail/drbd-user/2004-January/000014.html) Lars
> wrote that some directories should not be included. If that's so, does anybody
> have a list of what should/should not?

Mainly you should mirror the data space of your services, maybe the logs.

> Q: Should I use rsync instead, or in addition to drdb, for any non-mirrored
> directories?

Yes, or unison e.g. But again, mirroring _everything_ will not work. You 
have to exclude some directories and some files.

> Q. Given the above tasks, should I be looking at sticking in gigabit adapters
> on crossover instead?

That's better.

Helmut Wollmersdorfer