Hi,
I would normally post this to the drbd list but it so low traffic/low
volume (plus Austria might be asleep right now) I figured i'd ask
someone here in case they have gotten drbd working on centos. Right now
my system says i'm only the 971st person to even install it... It's
been out for years, so likely this just means version 8. But you'll
only see a couple of posts a day on there so far.
Here's a "HOWTO" for getting things to a point where you can
experiment
carefully with the mounting procedures, which is where the mystery comes
into view for the uninitiated <so don't follow it for production just
yet, it's under construction for eventual use by the Wiki if we can
answer some questions>:
Install Centos 5
during install make a filesystem called /drbd-netblock and give it 1GB and it
shows up as /dev/sda7
yum install drbd kmod-drbd
edit /etc/grub.conf to allow boot of the drbd kernel 2.6.18-8.1.6.el5 #1 SMP
reboot, the proper kernel should now be up.
modprobe drbd
umount /drbd-netblock filesystem so drbd can use it:
umount /drbd-netblock
edit /etc/drbd.conf /dev/sda7 is a 1GB filesystem I made during install called
/drbd-netblock
#############
global { usage-count yes; }
common { syncer { rate 10M; } }
resource r0 {
protocol C;
net {
cram-hmac-alg sha1;
shared-secret "secretphrase";
}
on box1.mydomain.com {
device /dev/drbd1;
disk /dev/sda7;
address 192.168.1.2:7789;
meta-disk internal;
}
on box2.mydomain.com {
device /dev/drbd1;
disk /dev/sda7;
address 192.168.1.3:7789;
meta-disk internal;
}
}
##############
drbdadm create-md r0 # Is this done on just the primary or both? I did it on
both.
drbdadm up all
you'll see:
[root@ ~]# ps ax | grep drbd
18063 ? S 0:00 [drbd1_worker]
18069 ? S 0:00 [drbd1_receiver]
18070 ? S 0:00 [drbd1_asender]
cat /proc/drbd will show both in secondary, as the drbd website howto shows, and
you can promote a node to primary:
drbdadm -- --overwrite-data-of-peer primary all
[root@ ~]# cat /proc/drbd
version: 8.0.3 (api:86/proto:86)
SVN Revision: 2881 build by buildsvn at c5-x8664-build, 2007-05-23 14:07:33
1: cs:Connected st:Primary/Secondary ds:UpToDate/UpToDate C r---
ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0
resync: used:0/31 hits:0 misses:0 starving:0 dirty:0 changed:0
My question is, when the howto says "The device is usable right away, go
ahead and create a filesystem if you haven't already", what do they
mean?
What are the following steps to get replication working?
I also made myself a 40GB partition called /replicated just in case I wanted to
use that.
How does the "device" statement in the .conf file (device /dev/drbd1;)
relate to any actual filesystem element? None right, it's just a name you
give your netblock correct?
Is the "disk" statement (disk /dev/sda7;) referring to my 1GB
filesystem space I created, that's what I should put right?
When you do the mount, are you doing "mount /dev/drbd1
/drbd-netblock1" or "mount /dev/drbd1 /replicated" ?
I figure someone here in the Centos crowd will have an answer(s) so we can
create a Wiki HOWTO for this. :-)
-krb
