opendev/system-config
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Add docs to replace a cinder volume

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We usually want to do these steps to avoid volume outages when
rackspace is doing updates.

Change-Id: Ie5de97484dddb9136c240baf46724646e39df67e
Signed-off-by: Paul Belanger <pabelanger@redhat.com>
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Paul Belanger 2017-03-23 13:22:47 -04:00
parent f4032071e4
commit d485cc7e11
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doc/source/sysadmin.rst
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@ -481,3 +481,63 @@ The following example increases the size of a volume to the maximum allowable::
NAME=volumename
sudo lvextend -l +100%FREE /dev/main/$NAME
sudo resize2fs /dev/main/$NAME
Replace an Existing Device
--------------------------
We generally need to do this if our cloud provider is planning maintenance to a
volume. We usually get a few days heads up on maintenance window, so depending
on the size of the volume, it may take some time to replace.
First thing to do is add the replacement device to the server, see
`Adding a New Device`_. Be sure the replacement volume is the same type / size
as the existing.
If the step above were followed, you should see something like::
$ sudo pvs
PV VG Fmt Attr PSize PFree
/dev/xvdb1 main lvm2 a-- 50.00g 0
/dev/xvdc1 main lvm2 a-- 50.00g 50.00g
Be sure both devices are in the same VG (volume group), if not you did not
properly extend the device.
.. note::
Be sure to use a screen session for the following step!
Next is to move the data from once device to another::
$ sudo pvmove /dev/xvdb1 /dev/xvdc1
/dev/xvdb1: Moved: 0.0%
/dev/xvdb1: Moved: 1.8%
...
...
/dev/xvdb1: Moved: 99.4%
/dev/xvdb1: Moved: 100.0%
Confirm all the data was moved, and the original device is empty (PFree)::
$ sudo pvs
PV VG Fmt Attr PSize PFree
/dev/xvdb1 main lvm2 a-- 50.00g 50.00g
/dev/xvdc1 main lvm2 a-- 50.00g 0
And remove the device from the main volume group::
$ sudo vgreduce main /dev/xvdb1
Removed "/dev/xvdb1" from volume group "main"
To be safe, we can also wipe the label from LVM::
$ sudo pvremove /dev/xvdb1
Labels on physical volume "/dev/xvdb1" successfully wiped
Leaving us with just a single device::
$ sudo pvs
PV VG Fmt Attr PSize PFree
/dev/xvdc1 main lvm2 a-- 50.00g 0
At this time, you are able to remove the original volume from openstack if
no longer needed.