Not directing this to you Michael or Sacha but something to consider while
we are on the topic of High Availability in general. If you will be doing
this for a customer/company and not your home setup I really recommend to
sit back from the technical side of 'I need HA' and quantify the business
reasons exactly why you need it. 

Things like: 

- What level of availability does the business *REALLY* require. (and not
the typical 24x7) This is a tough one to make customer understand that there
is no 100% uptime and everything will fail/need maintenance eventually.
What level of risk are they willing to agree with.

- What type of failover is needed a statefull and  full functionality, or is
it acceptable for current calls to drop and possibly run with reduced
functionality.

- With the HA how could the system still fail. (Internet outage, provider
failure, power outage, fire, theft)

- What are the real $ costs for having downtime. (per minute/hour/day)

- Other business impacts such as company image/reputation.

- Who is supporting the systems? (Will the first/second level support
understand the HA design can they actually support it?)  Putting in lots of
complex HA and not having knowledgeable people to support it will INCREASE
downtime and MTTR.

Having some of these questions answered will help you determine how complex
the HA needs to be and what you actually need to achieve.

Thanks
John





-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 
Sent: Thursday, October 12, 2006 9:21 PM
To: sacha panasuik
Cc: TAUG
Subject: Re: [on-asterisk] asterisk (trixbox) on xen 

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1


>>>>> "sacha" == sacha panasuik <[EMAIL PROTECTED]> writes:
    sacha> Thanks for your comments, I probably wasn't clear - I'd like
    sacha> to investigate keeping the entire filesystem for the asterisk
    sacha> virtual machine in sync on another physical server at the
    sacha> block level with something like DRDB ( http://www.drbd.org/).

  I didn't know about drdb.org

  It looks like it may be able to reduce a useable Xen redundant
installation from being three system (2 Xen hosts + 1 gndb disk host) or
4 systems, to 2 systems.

- -- 
]            Bear: "Me, I'm just the shape of a bear."          |  firewalls
[
]   Michael Richardson,    Xelerance Corporation, Ottawa, ON    |net
architect[
] [EMAIL PROTECTED]      http://www.sandelman.ottawa.on.ca/mcr/ |device
driver[
] panic("Just another Debian GNU/Linux using, kernel hacking, security
guy"); [


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