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[Ben Roble <ben.roble@xxxxxxxxxxxxx>]

Public bug reported:

The differential data (data committed to the disk after the initial
snapshot is created, but before the VM is shutdown) does not seem to be
carried over on resizes up on standard instances. This can be tested by
doing the following:

1. Create a cronjob that writes the time to a log file once every minute (* * * * * date >> /root/resize-test.log).
2. Resize the server up.
3. Examine the log file after the resize is complete, then revert the resize.
4. Compare it with the log file on the source after the revert is complete.

Data from the log file in one of my tests:
Destination (post-resize, pre-revert):

Sat Jan 31 12:10:01 UTC 2015
Sat Jan 31 12:11:01 UTC 2015
Sat Jan 31 12:12:01 UTC 2015
Sat Jan 31 12:13:01 UTC 2015
Sat Jan 31 12:14:01 UTC 2015
Sat Jan 31 12:15:01 UTC 2015
Sat Jan 31 12:16:01 UTC 2015
Sat Jan 31 12:17:01 UTC 2015
Sat Jan 31 12:18:01 UTC 2015
Sat Jan 31 12:19:01 UTC 2015
Sat Jan 31 12:25:01 UTC 2015
Sat Jan 31 12:26:01 UTC 2015
Sat Jan 31 12:27:01 UTC 2015
Sat Jan 31 12:28:01 UTC 2015
Sat Jan 31 12:29:01 UTC 2015
Sat Jan 31 12:30:01 UTC 2015
Sat Jan 31 12:31:01 UTC 2015
Sat Jan 31 12:32:01 UTC 2015
Sat Jan 31 12:33:01 UTC 2015
Sat Jan 31 12:34:01 UTC 2015

Source (post-resize, post-revert):

Sat Jan 31 12:04:01 UTC 2015
Sat Jan 31 12:05:01 UTC 2015
Sat Jan 31 12:06:01 UTC 2015
Sat Jan 31 12:07:01 UTC 2015
Sat Jan 31 12:08:01 UTC 2015
Sat Jan 31 12:09:01 UTC 2015
Sat Jan 31 12:10:01 UTC 2015
Sat Jan 31 12:11:01 UTC 2015
Sat Jan 31 12:12:01 UTC 2015
Sat Jan 31 12:13:01 UTC 2015
Sat Jan 31 12:14:01 UTC 2015
Sat Jan 31 12:15:01 UTC 2015
Sat Jan 31 12:16:01 UTC 2015
Sat Jan 31 12:17:01 UTC 2015
Sat Jan 31 12:18:01 UTC 2015
Sat Jan 31 12:19:01 UTC 2015
Sat Jan 31 12:20:01 UTC 2015 <-
Sat Jan 31 12:21:01 UTC 2015 <- 3 minutes worth of logs that didn't get copied over.
Sat Jan 31 12:22:01 UTC 2015 <-
Sat Jan 31 12:38:01 UTC 2015

Another way to make this bug obvious is to write multiple GB of data
during the resize up process and notice how it is entirely lost when the
resize completes.

** Affects: nova
     Importance: Undecided
     Assignee: Ben Roble (ben-roble)
         Status: New

** Changed in: nova
     Assignee: (unassigned) => Ben Roble (ben-roble)

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to OpenStack Compute (nova).
https://bugs.launchpad.net/bugs/1421707

Title:
  Differential data not carrying over on resize up

Status in OpenStack Compute (Nova):
  New

Bug description:
  The differential data (data committed to the disk after the initial
  snapshot is created, but before the VM is shutdown) does not seem to
  be carried over on resizes up on standard instances. This can be
  tested by doing the following:

  1. Create a cronjob that writes the time to a log file once every minute (* * * * * date >> /root/resize-test.log).
  2. Resize the server up.
  3. Examine the log file after the resize is complete, then revert the resize.
  4. Compare it with the log file on the source after the revert is complete.

  Data from the log file in one of my tests:
  Destination (post-resize, pre-revert):

  Sat Jan 31 12:10:01 UTC 2015
  Sat Jan 31 12:11:01 UTC 2015
  Sat Jan 31 12:12:01 UTC 2015
  Sat Jan 31 12:13:01 UTC 2015
  Sat Jan 31 12:14:01 UTC 2015
  Sat Jan 31 12:15:01 UTC 2015
  Sat Jan 31 12:16:01 UTC 2015
  Sat Jan 31 12:17:01 UTC 2015
  Sat Jan 31 12:18:01 UTC 2015
  Sat Jan 31 12:19:01 UTC 2015
  Sat Jan 31 12:25:01 UTC 2015
  Sat Jan 31 12:26:01 UTC 2015
  Sat Jan 31 12:27:01 UTC 2015
  Sat Jan 31 12:28:01 UTC 2015
  Sat Jan 31 12:29:01 UTC 2015
  Sat Jan 31 12:30:01 UTC 2015
  Sat Jan 31 12:31:01 UTC 2015
  Sat Jan 31 12:32:01 UTC 2015
  Sat Jan 31 12:33:01 UTC 2015
  Sat Jan 31 12:34:01 UTC 2015

  Source (post-resize, post-revert):

  Sat Jan 31 12:04:01 UTC 2015
  Sat Jan 31 12:05:01 UTC 2015
  Sat Jan 31 12:06:01 UTC 2015
  Sat Jan 31 12:07:01 UTC 2015
  Sat Jan 31 12:08:01 UTC 2015
  Sat Jan 31 12:09:01 UTC 2015
  Sat Jan 31 12:10:01 UTC 2015
  Sat Jan 31 12:11:01 UTC 2015
  Sat Jan 31 12:12:01 UTC 2015
  Sat Jan 31 12:13:01 UTC 2015
  Sat Jan 31 12:14:01 UTC 2015
  Sat Jan 31 12:15:01 UTC 2015
  Sat Jan 31 12:16:01 UTC 2015
  Sat Jan 31 12:17:01 UTC 2015
  Sat Jan 31 12:18:01 UTC 2015
  Sat Jan 31 12:19:01 UTC 2015
  Sat Jan 31 12:20:01 UTC 2015 <-
  Sat Jan 31 12:21:01 UTC 2015 <- 3 minutes worth of logs that didn't get copied over.
  Sat Jan 31 12:22:01 UTC 2015 <-
  Sat Jan 31 12:38:01 UTC 2015

  Another way to make this bug obvious is to write multiple GB of data
  during the resize up process and notice how it is entirely lost when
  the resize completes.

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