Hi Jay,
We have had similar issues with extending attached volumes that are
iSCSI based. In that case the VM has to be forced to rescan the scsi bus.
In this case I am not sure if there needs to be a change to Libvirt or
to rbd or something else.
I would recommend reaching out to John Bernard for help.
In fact, I'm ok with delayed resize (upon power-cycle), and it's not an
issue for me that VM don't detect changes immediately. What I want to
understand is that changes to Cinder (and, thus, underlying changes to
CEPH) are safe for VM while it's in active state.
Hopefully, Jon will help with this question.
Thank you!
On 6/23/18 8:41 PM, Jay Bryant wrote:
On Sat, Jun 23, 2018, 9:39 AM Volodymyr Litovka <doka...@gmx.com
<mailto:doka...@gmx.com>> wrote:
Dear friends,
I did some tests with making volume available without stopping VM.
I'm
using CEPH and these steps produce the following results:
1) openstack volume set --state available [UUID]
- nothing changed inside both VM (volume is still connected) and CEPH
2) openstack volume set --size [new size] --state in-use [UUID]
- nothing changed inside VM (volume is still connected and has an
old size)
- size of CEPH volume changed to the new value
3) during these operations I was copying a lot of data from external
source and all md5 sums are the same on both VM and source
4) changes on VM happens upon any kind of power-cycle (e.g. reboot
(either soft or hard): openstack server reboot [--hard] [VM uuid] )
- note: NOT after 'reboot' from inside VM
It seems, that all these manipilations with cinder just update
internal
parameters of cinder/CEPH subsystems, without immediate effect for
VMs.
Is it safe to use this mechanism in this particular environent (e.g.
CEPH as backend)?
From practical point of view, it's useful when somebody, for
example,
update project in batch mode, and will then manually reboot every VM,
affected by the update, in appropriate time with minimized downtime
(it's just reboot, not manual stop/update/start).
Thank you.
--
Volodymyr Litovka
"Vision without Execution is Hallucination." -- Thomas Edison
--
Volodymyr Litovka
"Vision without Execution is Hallucination." -- Thomas Edison
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