[Users] Live Migration Optimal execution

[Nipun Arora]

I have a few followup queries. For my purposes, I have modified the live
migration script to allow me to do cloning... i.e. I start both the
containers instead of deleting the original. I need to do this "cloning"
from time to time for the same target container...

1. Which means that lets say we cloned container C1 to container C2, and
let both execute at time t0, this works with no apparent loss of service.

2. Now at time t1 I would like to again clone C1 to C2, and would like to
optimize the rsync process as most of the ploop file for C1 and C2 should
still be the same (i.e. less time to sync). Can anyone suggest what would
be the best way to realize the second point?


As a background: I use the following command when I do vzmigrate, I was
wondering if there are any other options that need to be used, for e.g. as
reported vzfsync etc,

vzmigrate --online --times --live 192.168.122.10 101

Starting live migration of CT 101 to 192.168.122.10

Preparing remote node

Syncing private

Usage: vzfsync {-s|-d} [-n] file [file ...]

       -s, --sync               do fsync()

       -d, --datasync           do fdatasync()

       -n, --dontneed           do fadvise(DONTNEED)

Live migrating container...

The following has been used to create the container

vzctl create $1 --ostemplate centos-6-x86_64 --config basic --layout ploop



Thanks

Nipun

On Sat, Nov 22, 2014 at 12:09 PM, Nipun Arora <nipunarora2512 at gmail.com>
wrote:

> Hi All,
>
> I was wondering if anyone can suggest what is the most optimal way to do
> the following
>
> 1. Can anyone clarify if ploop is the best layout for minimum suspend time
> during live migration?
>
> 2. I tried migrating a ploop device where I increased the --diskspace to
> 5G, and found that the suspend time taken by live migration increased to 57
> seconds (mainly undump and restore increased)... whereas a 2G diskspace was
> taking 2-3 seconds suspend time... Is this expected?
>
> 3. I tried running a write intensive workload, and found that beyond
> 100-150Kbps, the suspend time during live migration rapidly increased? Is
> this an expected trend?
>
> I am using vzctl 4.7, and ploop 1.11 in centos 6.5
>
> Thanks
> Nipun
>
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