[DRBD-user] DRDB on one host

Dan Barker dbarker at visioncomm.net
Thu May 15 00:00:09 CEST 2014

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

From: drbd-user-bounces at lists.linbit.com [mailto:drbd-user-bounces at lists.linbit.com] On Behalf Of Csanad Novak
Sent: Tuesday, May 13, 2014 5:47 PM
To: Arnold Krille; drbd-user at lists.linbit.com
Subject: Re: [DRBD-user] DRDB on one host

Hi Arnold,

I guess the challenge here is that the instance-storage get reseted completely (back to the point when its just a raw device without partitions) on every stop/start cycle.

Currently I’m using a less than satisfactory solution on non critical servers, as follow:

I’ve got mounted my instance-storage as /dev/sdb1 to /var
I’ve got mounted my ebs device as /dev/sdc1 to /mnt/var-backup

I’ve lsyncd configured to sync from /var to /mnt/var-backup

I’ve wrote a little bash script for auto partitioning and mounting. When the instance get stopped for any reason the instance storage gets reseted and the whole /var directory destroyed. After boot up my script repartitioning the instance storage, mount it, and then automatically rsync back the data from /mnt/var-backup.

There is several issue with this architecture, but the biggest one with lsyncd, which wasn’t designed for this. If I cloud change lsyncd to drbd, that would great.

I must stress again: instance-storage is a local hard-disk based block device, while the ebs storage is a network attached block device.



From: Arnold Krille arnold at arnoldarts.de<mailto:arnold at arnoldarts.de>
Reply: Arnold Krille arnold at arnoldarts.de<mailto:arnold at arnoldarts.de>
Date: 14 May 2014 at 6:18:25
To: drbd-user at lists.linbit.com<mailto:drbd-user at lists.linbit.com> drbd-user at lists.linbit.com<mailto:drbd-user at lists.linbit.com>
Subject:  Re: [DRBD-user] DRDB on one host

On Tue, 13 May 2014 09:57:21 +1200 Csanad Novak
<csanad at pixelfusion.co.nz<mailto:csanad at pixelfusion.co.nz>> wrote:
> Recently on the latest AWS Summit I’ve seen an interesting setup for
> utilising the AWS EC2 instance storage. The instance storage is the
> local filesystem on the Amazon cloud, unfortunately it is not
> persistent - all data get lost if the instance stops. For persistent
> storage one must use an so called EBS volume, which is a network
> attached block device. Unfortunately the EBS storage performance is
> varies, depending on the neighbour instances’ traffic. An ideal world
> one can use the instance storage without the worry of data loss.
> On the latest AWS Summit a presenter proposed an architecture where
> the instance storage was utilised and was synced with DRBD to the EBS
> block
> device. http://www.slideshare.net/AmazonWebServices/so-you-think-you-are-an-aws-ninja-dean-samuels -
> slide 11.
> I wonder how an example config would looks like. I went trough
> quickly on the tutorials, but couldn’t find any example with one host
> setup.

drbd on one host. Isn't that what raid/md is?

I haven't had a chance to play with aws but if both ebs volumes and the
instance-storage are block devices, it should be easy to mirror them
with md or lvm.

- Arnold
drbd-user mailing list
drbd-user at lists.linbit.com<mailto:drbd-user at lists.linbit.com>
Kind regards,

[cid:image001.gif at 01CF6F9E.577D9E80]

Csanad Novak
Technical Lead
P / 09 353 1234<tel://09%20353%201234>
M / 021 060 1531<tel://09%20353%201234>
E / csanad at pixelfusion.co.nz<mailto:wouter at pixelfusion.co.nz>

A / SUITE 403 "FORBIDDEN", THE IRON BANK, 150 KARANGAHAPE RD, AUCKLAND / PIXEL FUSION LTD, PO BOX 68 564, NEWTON, AUCKLAND / MAP<http://maps.google.co.nz/maps?cid=7370666879334476751&q=Pixel+Fusion>
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