DRBD Vmware Replication

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[falko]

Try 192.168.0.20 instead of 192.168.0.10.

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[houms]

I was so excited to try this howto on vmware failover and replication on etch, but I do believe that it is not thorough enough and does not go into enough detail. I have tried this install several times and without success. I am so frustrated, cause I would love to get this working, but the instructions do not make complete sense… for example in the drbd.conf file your example shows a 172.x.x.x address. Where did you get this from? Like I said either I missed the boat on this or you have just not explained the setup well enough in my opinion. Though I am thankful for your time and efforts, I would be extremely greatful if someone can help or revise the howto so that it explains the 2 nic configuration a bit better, cause that part doesn’t make much sense, and also a little more explanation on the heartbeat and vmstart script, cause everytime I get to this part my vm disappears. Something about the vmware is not register and to register it. Doesn’t seem like drbd is working properly cause my vm is not under /var/vm.. Also are you supposed to create the same vm on both nodes or should it replicate from node 1 to 2?
As you can see I hae a lot of questions about this process. I think a diagram of the setup would also be very helpful….
Again thanks for all your time and efforts. Hope someone can help

[thanis]

Hi Houms,

Unfortunately, this setup was NOT intended for people without good linux/vmware knowledge.

* The "register" error you get is due to a faulty VMWare installation (check google)
* The 172.x.x.x address, is what it is, it is just an address from a private address range (e.g. 192.168.0.0/16, 172.16.0.0/20 and 10.0.0.0/8). Choose your own is the message here
* No you don't need to create separate VM's on both machines. DRBD is like said in the tutorial a REPLICATION mechanism. So, create your VM in the /var/vm directory AFTER mounting it and it will be replicated in REAL-TIME between your servers)
* You should check the "references" at the bottom of the tutorial, there are links to the heartbeat manual ...
* The VMSTART script just starts the VM in case of failover, changing the VM filename should be enough for a default setup

Also, a lot of people have been able to use this tutorial without issues and it still runs as a production setup in several companies ...

Grtz,
Thanis (the author)

[houms]

@thanis
Thank you very much for your response.. I really appreciate it. I consider myself to have pretty good knowledge of linux, but hey what do i know..... vmware not so much. couple of questions if you would be so kind to respond. Is this type of setup possible using xen instead of vmware?
I guess my confusion for the 172 address is that you then use address ranges in the 192. subnet for heartbeat configuration...I am wondering when you say using two nics in the beginning of the tutorial what exactly that means..are both "nodes" using two nics on the same network (LAN).. or is one of the nics connecting to each other via crossover cable? Or are they seperated, one nic on the LAN and the other on a seperate VLAN?
Cause everytime i have done this tutorial, the drbd part works flawlessly. I can mount /var/vm. I can see they are synched but I am sure i am missing something on the hearbeat setup because as soon as i'm done confirguring the hearbeat setup, i cannot start the vm's it keeps giving me vm config file not registered....Not only that but then the /var/vm directory is mysteriously empty..?
Nonetheless I will read the references you mentioned and see if I can't get this going..I really do appreciate your efforts. Thank you again.

[thanis]

Hi,

Actually, using Xen is not an issue, the only "changes" on my part are the heartbeat config and the vmstart script. The rest is pretty generic.

For the 2 NIC's, I was using one nic for DRBD replication and the other for network/heartbeat. But actually, using only 1 NIC works just as well though That's why you see 2 addresses.

For the /var/vm being empty, that's probably normal since my script stops DRBD and then mounts it, if there is an error, the /var/vm does not get mounted ergo, it stays empty

Grtz,
Thanis

[houms]

Thanis thank you for that clarification....Again I cannot thank you enough for taking your time to respond to my silly inquiries....so you could use drbd and heartbeat on the same nic right? I assume performance will take a hit? so in your howto your using drbd via crossover cable between the nodes...right?
I will try and play with it again hopefully this weekend... So if /var/vm is not mount.. is there a way to find out why... I keep getting this error in the vmware-server-console when trying to start the vm, it keeps saying the file is not registered, run some register -s command... Sorry I am not in front of the nodes right now....but no matter what i did even copying the command it told me to run, it was not working. Any advice on what I missed that may have caused the error?
In your last response you mentioned a faulty vmware install, but i have installed vmware on etch several times using the same howto you referenced and have never had any problems with it...? Not sure if it is indeed vmware install related...If it is, can you give some insight as to what about the install may not be proper?

I am really trying to get this going with xen as well. I would like to try and do this with hardy 8.04, since howtoforge has a howto on this... And since ubuntu includes the newest xen packages, and has drbd intergrated(version 8 i think..), I think this would be ideal to have a primary-primary setup for a live migration configuration. using these as a base of sorts...
http://www.howtoforge.com/ubuntu-8.0...u-repositories
http://www.gossamer-threads.com/lists/drbd/users/14627

Thanis, do you think its possible? if so, do you have any suggestions...?If you or anyone else would like to help me put a howto together for this, I would be eternally greatful..thanks again for your response. I really look forward to hearing the responses.

[thanis]

Hi Houms, if the /var/vm folder is empty, please type "mount" and you should see it there. If not, it means it is NOT mounted and you should do that:
mount -t ext3 /dev/drbd0 /var/vm

I'll check out the new Ubuntu distro as well