[DRBD-user] Re: sdb or sdbx?

Ugo Bellavance ugob at camo-route.com
Thu Apr 6 13:56:04 CEST 2006

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Andreas J. Koenig wrote:
>>>>>> On Wed, 05 Apr 2006 17:41:04 -0400, Ugo Bellavance <ugob at camo-route.com> said:
> 
>   > 3- Start drbd
> 
>   > # service drbd start
> 
>   > 4- Make the primary primary
> 
>   > #  drbdadm -- --do-what-I-say primary all
> 
> In a guide, I would not use "all" but the resource name, in your
> example drbd0. I'd probably choose an example that does not confuse
> the reader: if I'd demonstrate setting up mysql, I'd call it
> drbd_mysql.

Good idea,

> 
>   > 5- Check the status
> 
>   > # watch cat /proc/drbd
> 
>   > 6- Once in sync, create a filesystem on the drbd device (on both servers)
> 
>   > # mkfs -t ext3 /dev/drbd0
> 
> Only on primary is enough. Don't know if it breaks something to do it
> on both.

Ok.  I guess it gets replicated to the secondary.

> 
>   > 7- Create a mount point (both servers)
> 
>   > # mkdir /drbd
> 
>   > 8- Mount the drbd device on it (only on the primary)
> 
>   > # mount /dev/drbd0 /drbd
> 
>   > Finally, integrate with Heartbeat (which I haven't understood yet either.
> 
> It means that you do not ever do steps 3-8 again yourself. Steps 3-8
> are ok to learn the basics and play with them, but as soon as
> heartbeat does it for you, you let it alone. So
> 
>   9 - Let drbd alone because it shall be owned by heartbeat (on
>       current primary)
> 
>   # umount /drbd; drbdadm down drbd0;
> 
> As heartbeat usually involves starting a service that uses the mounted
> disk you would now disable that service from being started by the OS
> 
>  10 - Disable OS from starting mysql (on both nodes)
> 
>   # rm /etc/rc?.d/[SK]*mysql

or chkconfig --del mysql

> 
> Talk about the need to prevent your upgrade mechanism (here yum) from
> reinstalling those start/stop symlinks.

Ok

> 
>  11 - Configure heartbeat (on both nodes)
> 
>   # involves authkeys, haresources, and ha.cf; see
>   # http://linux-ha.org/DRBD/GettingStarted
> 
>  12 - Start heartbeat (on both nodes)
> 
> This will bring up everything in the desired order and only on the
> machine that is allowed to do it: make the DRBD primary, mount the
> disk, ifconfig an ethernet alias interface, start mysql.
> 
>  13 - test failover (on current primary)
> 
>   # hb_standby          # http://linux-ha.org/hb_standby
>   # hb_takeover         # http://linux-ha.org/hb_takeover

Nice, I didn't know about those 2 commands

> 
>  14 - test failover (on the other node)
> 
>   # hb_takeover
>   # hb_standby
> 
>   > Am I ok?  One question I had is:
> 
>   > I've seen some examples using partition devices instead of disk
>   > devices in drbd.conf.  How do they do that?  What kind of partition do
>   > they create on the disk to be able to put a drbd device over it?  My
>   > example uses /dev/sdb, which is the 2nd SCSI disk.  I didn't create
>   > any partition on it, in fact, the partition is the drbd device and I
>   > created the FS on the drbd device.  Is that OK?  Would it be better to
>   > use a partition instead?  How?
> 
> pass
> 

Ok, and once my guide is done, how can I make it easy for people to read 
it (put it on linux-ha or drbd.org's web site)?

Regards,





More information about the drbd-user mailing list