[Users] Increase storage domain

[Alan Johnson]

On Sat, Aug 11, 2012 at 5:56 PM, Ayal Baron <abaron at redhat.com> wrote:

> ----- Original Message -----
> > Hi,
> >
> > pvresize doesn't work, still same size.
> >
> > How do i disconnect the iscsi session?
> >
> > Between disconnecting and ovirt connect again, will i loose
> > connection to my VMs?
>
> Of course you would.  Your VMs would automatically pause.
> I doubt this is what you want.
> What you can do prior to running pvresize is run:
> iscsiadm -m session -R
> Hope this helps.
>
>
Did anyone have any success with this?  I was unable to get pvdisplay to
show the new size until I rebooted the hosts and ran pvresize.  I started
with a 1TiB volume on our Equallogics SAN and set it to 5TiB.  I put my
non-SPM host into maintenance and ran pvresize on the SPM.  I did not
expect this to work because of previous experience and this thread.
 pvresize said it resized, but pvdisplay showed 1023GiB instead of 1TB, so
it shrunk it a tiny bit?

Next, I tried `iscsiadm -m session -R` and then pvresize which said it
resized 0 PVs and pvdisplay confirms no change.  I did a `iscsiadm -m node
-T <iqn> -u` then `iscsiadm -m node -T <iqn> -l` followed by pvdisplay.
 pvdisplay spewed an IO error message for the PV and each LV and I noticed
that the device had changed from /dev/mapper/<UUID> to /dev/sdf, which
explains why it thought the PV and all the other LVs were missing.  I
should have deactivated the LVs/VG/PV first I supposed, and then
reactivated them afterwords.

Anyway, this gave me pause, but I'm still pre-production, so I went ahead
and did a pvresize, which did nothing,and pvdisplay gave the same output,
including errors, as before.  So, I rebooted the host, activated the host,
ran pvresize on the host, and all is as desired.

I then rebooted my other host and all was well when it came up.  I can deal
with rebooting each host if necessary, but it is certainly not ideal.  Has
anyone worked out the correct steps make this happen without rebooting the
hosts and minimal VM interruption?  I might try it a couple more times if
not.

The bigger question is, how do I get the engine to see the new size?  It is
still seeing 1TB.  Stopping and starting (why no restart on
/etc/init.d/ovirt-engine?) did not cause a refresh.  Oop!  There it went,
just as I was typing this, I saw it change in the window behind this one.
 So, was it just a cache time out, or did I need to restart the engine as
well?

An ideal setup would be for the engine to detect the change and run the
necessary commands on each host.  If auto detection is not reasonable, an
option in the GUI to tell the engine the LUN has changed would be nearly as
good.

Alternately, would it just be better to create a new LUN on the iSCSI
target and add it to the storage domain?  Is that even doable?  Certainly
it is as simple as adding a new PV to the VG in LVM, but does the
engine/GUI support it?  It seems a bit more messy than growing an existing
domain from an iSCSI target point of view, but are there any technical down
sides?

Eventually, I think I'll look into filing a feature request, so I would
appreciate if some one could point me in the right direction, but let's
hash out what makes sense here before doing that.
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