| Re: Re: vzmigrate standby mode [message #42714 is a reply to message #42712] |
Fri, 13 May 2011 18:28   |
Jean-Marc Pigeon
Messages: 27
Registered: October 2007
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Junior Member |
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On Fri, 2011-05-13 at 12:25 -0400, Sterling Windmill wrote:
> The problem with the lsyncd approach is it doesn't guarantee
> filesystem consistency. If you're running a database or any other
[...]
Agree with you, difficult to be an effective solution with
a real server running database, filesystem consistency
could be a real issue
> .
>
>
> vzctl chkpnt and restore guarantees consistency in that the state of
> the container is dumped when the checkpoint is created and restored
[...]
> period of time and wouldn't be ideal as a means of taking backups of
> production systems on a regular basis.
Using vzmigrate as starting point, I wrote a small
shell, with a small VPS (1.2 Gig Bytes) as test bench,
the preliminary result are (so fare) encouraging.
"standby" is done between 2 HOST on local network
Syncing private
Live migrating VPS...
Resuming local VPS
Times:
Second rsync: 0.507628 sec
Quota Generation: 0.00138903 sec
Suspended time: 0.631432 sec
Total time: 6.47325 sec
less than one second of suspend is good enough to me,
It is true the data-base within this test VPS
is not a very active one.
Keep in mind, there is many task (data dump transfer,
reload, ...) which can be done on the "standby"
VPS while the production one already resume task.
>
>
> Checkpointing for this purpose would probably only make sense for a
> container with data that doesn't change over time. A simple
> application server that relies on an external database for instance.
Agree with you.
Critical issue is the "suspend" time, if production
VPS is in very "volatile" data context, "suspend"
time could be a real issue.
>
>
> lsyncd is interesting though, I haven't heard of it before and will
> definitely be doing some research.
Agreed
>
>
> Best regards,
> Sterling
>
>
> On Fri, May 13, 2011 at 5:54 AM, Aleksandar Ivanisevic
> <aleksandar@ivanisevic.de> wrote:
> Jean-Marc Pigeon <jmp@safe.ca> writes:
>
> > Hello,
> >
> >
> > I think it will be very convenient to have a way to
> > prepare/clone a VPS ready to start at moment notice
> > (standby mode), a kind of action ready backup.
>
>
> We do it with lsyncd http://code.google.com/p/lsyncd/ that
> allows only
> changed files to be rsynced. Put /vz/private/veidt and
> /etc/vz/conf/veid.conf in it and you are all set.
>
> Much easier on the machines, no cron necessary and the backups
> can be
> made really close to production.
>
> [...]
>
>
>
--
A bientôt
============================================================ ==============
Jean-Marc Pigeon Internet: jmp@safe.ca
SAFE Inc. Phone: (514) 493-4280
Fax: (514) 493-1946
Clement, 'a kiss solution' to get rid of SPAM (at last)
Clement' Home base <"http://www.clement.safe.ca">
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