<div dir="ltr"><div><div>Hi Robert,<br>I think the problem is related to the fact that there is a (LVM) partition on top of the drbd device. I tried different configurations and if I use a raw device for the drbd resource and then I use the drbd device without partitions as a PV the problem disappear. Anyway, I dont know if this is really a problem because there is not overlap at all. I (double) checked this using fdisk on /dev/sde and on /dev/drbd2. Both show me a partition that starts at sector 2048. The only problem is that when I use lsblk I see that inside /dev/sde there are 2 devices: /dev/sde1 and /dev/drbd2. I'd like to know if this can cause some kind of problem with performance or data corruption....<br>Probably the question is: can I use a raw device as PV? As suggested <a href="https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/LVM_components.html#multiple_partitions">here</a> it is possible but there is some problem with the management if I need to enlarge the volume but I don't need this.<br></div><br></div>Marco<br><div><br><div><div><div><br> <br></div></div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">2017-03-27 9:54 GMT+02:00 Robert Altnoeder <span dir="ltr"><<a href="mailto:robert.altnoeder@linbit.com" target="_blank">robert.altnoeder@linbit.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">The system looks for partition information at a certain offset on a<br>
storage device. If DRBD is used to write directly to a raw storage<br>
device, the effect of partitioning the DRBD device on the backing device<br>
is the same as if the backing device had been partitioned directly with<br>
no DRBD involved.<br>
Therefore, the system will see the partition information on the backing<br>
device.<br>
<br>
DRBD internal meta data is written to the end of the backing device<br>
(without using any partitioning). The space occupied by the internal<br>
meta data will be missing from the DRBD device's size (the DRBD device's<br>
size will be the backing device's size minus the space reserved for<br>
internal meta data).<br>
<div><div class="h5"><br>
On 03/25/2017 02:57 PM, Yannis Milios wrote:<br>
><br>
> Not 100% sure but the first 'partition' could be where drbd stores<br>
> metadata?<br>
><br>
> Your setup should be fine as long ad you can deal in an easy manner<br>
> with future resizing of the backing device (sde).<br>
><br>
> Yannis<br>
><br>
> root@iscsi2 ~]# lsblk<br>
> NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT<br>
> ........<br>
> sde 8:64 0 3,7T 0 disk<br>
> ├─sde1 8:65 0 3,7T 0 part<br>
> └─drbd2 147:2 0 3,7T 0 disk<br>
> --<br>
> Sent from Gmail Mobile<br>
><br>
</div></div>br,<br>
--<br>
Robert Altnoeder<br>
<a href="tel:%2B43%201%20817%2082%2092%200" value="+43181782920">+43 1 817 82 92 0</a><br>
<a href="mailto:robert.altnoeder@linbit.com">robert.altnoeder@linbit.com</a><br>
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