drbd and lvm - only qemu images? no backup, no iso ? why ?

[tytanick]

Hi guys,
As doing by this howto http://pve.proxmox.com/wiki/DRBD
I made on /dev/sdb1 - DRBD on two nodes and then on top of it LVM group
I added LVM to storage in proxmox cluster but i cant store iso teplates and backups there, why ?
http://scr.hu/2o2c/8kpa4

Meaby i should add PV ? How can i do this ?

 

[m.ardito]

Hi guys,
As doing by this howto http://pve.proxmox.com/wiki/DRBD
I made on /dev/sdb1 - DRBD on two nodes and then on top of it LVM group
I added LVM to storage in proxmox cluster but i cant store iso teplates and backups there, why ?

see
http://pve.proxmox.com/wiki/Storage_Model

LVM is a block device storage type, so it cannot host files/folders directly, it can only host filesystems

you can use any other suitable storage type, as local or NFS, or else (see above link)

Marco

 

[udo]

Hi guys,
As doing by this howto http://pve.proxmox.com/wiki/DRBD
I made on /dev/sdb1 - DRBD on two nodes and then on top of it LVM group
I added LVM to storage in proxmox cluster but i cant store iso teplates and backups there, why ?
http://scr.hu/2o2c/8kpa4

Meaby i should add PV ? How can i do this ?

Hi,
for qcow2, templates and backups you need an filesystem (local) or an shared filesystem like an nfs-mount.
On lvm-storage you got "only" logical volumes, which are the raw vm-disks.

add PV?? mean what? You can create an own logical volume and create an filesystem on there - but with an normal filesystem (ext3/4, xfs...) you can mount this filesystem on one node only at one time.

Udo

 

[tytanick]

so i have to create ext4 filesystem on
drbd -> PV -> VG -> ext4 ?

--- Volume group ---
VG Name drbdvg

how can i do this ? ?

lvcreate -n data drbdvg
mkfs -j ext4 /dev/drbdvg/data

and then i could mount it normally ?

Tell me will this be working ok with DRBD ? i can normlally do all the things and nothing will bad happen ?

 

[udo]

so i have to create ext4 filesystem on
drbd -> PV -> VG -> ext4 ?

--- Volume group ---
VG Name drbdvg

how can i do this ? ?

lvcreate -n data drbdvg
mkfs -j ext4 /dev/drbdvg/data

and then i could mount it normally ?

Tell me will this be working ok with DRBD ? i can normlally do all the things and nothing will bad happen ?

Hi,
it's "drbd -> pv -> vg -> lv with ext4".

for lvcreate you need an size like "-L 50GB".
And yes you can mount it normaly - but only at one node!

Udo

 

[tytanick]

only at one node ?
So what is the point

how can i do this and mount on both nodes so that drbd will do ad live migration also and backups nad other stuff, ???

 

[acidrop]

You can do it only by storing vms directly on lvm volume (without filesystem).
qcow2 and other filebased vm disk formats are not allowed in this setup.
Your backups must be stored on separate storage for example NFS.
To acomplish this configuration follow this guide carefully:

http://pve.proxmox.com/wiki/DRBD

create drbd resource
create pv -> vg on drbd

and finally...

Go to the Proxmox VE web interface to 'Configuration/Storage' and click on the red arrow and select 'Add LVM group'.

You will see the previously created volume group (drbdvg), select this and give a Storage Name (cannot be changed later, so think twice), and enable the sharing by click the 'shared' box.

Now you have a shared storage space which you can slice and host vms on it.
Because drbd works in dual primary mode you can also live migrate vms between two nodes.

 

[tytanick]

yeah i have it working already with VM's but i didnt know that i cant store backups on this synced drbd - weak solution .......

So drbd cant be used on two primary/primary nodes with ext4 on it ? hmmmm
Little stupid

 

[acidrop]

of course not...ext4 is not considered a clustered filesystem.
If you do it then your vms will get corrupted since ext4 is not allowed to be mounted from both nodes at the same time.
If you really need qcow2 and it's snapshot capability then try glusterfs instead of drbd.

 

[tytanick]

and why most of the people doesnt use glusterfs if it is so much better ?

Accually i just want to have always fresh data of all VMS on both nodes and possibility to use live migration, and also ability to have backups synced on each node ....

meaby glustefs is the way to go instead drbd. are they some CONS after glusterfs ?

 

[acidrop]

Each storage system has it's pros and cons.
I didn't say that glusterfs is perfect.I mentioned it as a second option to achieve your goals.
Personally I am using two node drbd cluster for vms (no HA) and a NAS (nfs server) for backups.
I can live migrate vms with drbd (dual primary mode) and put backups on NAS.
There is no need for me ta have also backups replicated on another storage in real time.