[DRBD-user] Very newbie question

Lars Ellenberg Lars.Ellenberg at linbit.com
Tue May 25 13:35:59 CEST 2004

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


/ 2004-05-24 07:54:51 -0400
\ Gary Baker:
> I look forward to a response to my question from the list.

just because my typpical response time is a few hours, this does not
mean that I work all day and night... and sometimes, especcially on
Weekends, we are all just off somewhere...

> Also, based
> on an aswer to another question, since gentoo uses devfs, should I be
> specifying /dev/nbd/0 instead of /dev/nb0 in my drbd.conf file?

yes.


> I have done an rsync of the production server (called DS) to it's
> backup (called DS2). I have also rsync'ed that to the cluster
> experiment
> box (called DS3). DS2 and DS3 are connected to the main net through
> eth0
> (10/100Mbit) and a crossover cable on eth1 (10/100Mbit). I have
> installed heartbeat on DS2 and DS3 and tested the failover and it
> works.
> I have installed DRBD on DS2 and DS3
> DS2 = hda3 is root partition (reiserfs), which I want mirrored to DS3
> DS3 = sda3 is root partition (reiserfs), which will be the mirror of
> DS2

no.

DRBD is not intended to mirror the *system*.  which is mostly "static"
anyways, you don't need live replication of /bin/bash, it won't change
that often in the next month...
and it won't work anyways (without major tweaking), since only one node
at a time has exclusive access to the device.

it is intended to mirror more or less rapidly changing data partitions.

> I am now ready to test my cluster, but I am not fully understanding
> how DRBD works with existing file systems. What must I do to create
> the mirror/failover between the two?

with 0.6.x, you just configure DRBD to use the partition in question as
its lower level device, and from then on only access that one through
DRBD. you want to read the howto, and the Data Redundancy By DRBD
article.

> Should I be trying to mirroring my entire root partition?

certainly not, unless you want to have one node stuck in its initramdisk
until the other one fails... :-)

> Do I mirror only part?

you mirror your data partitions.

> I am worried that I will have problems
> since DS3 is SCSI and DS2 is IDE.

why?
no worries.


	Lars Ellenberg



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