Re: [vserver] Re: [Freedombox-discuss] [vserver] Re: A software architecture for the FreedomBox

From: Herbert Poetzl <herbert_at_13thfloor.at>
Date: Fri 15 Apr 2011 - 16:36:13 BST
Message-ID: <20110415153613.GF3958@MAIL.13thfloor.at>

On Fri, Apr 15, 2011 at 12:27:21PM +0200, Jon Bendtsen wrote:
> On 15/04/2011, at 12.20, Gordan Bobic wrote:

>> Jon Bendtsen wrote:
>>> On 15/04/2011, at 01.01, Martin Fick wrote:
>>>> --- On Thu, 4/14/11, Gordan Bobic <gordan@bobich.net> wrote:
>>>>>> --- On Thu, 4/14/11, Gordan Bobic<gordan@bobich.net>
>>> [cuuuuuut]
>>>>> However
>>>>> - what use-case do you have where one guest will fail
>>>>> unrecoverably on one machine but resumes working on another
>>>>> machine with the exact same FS? In what case would a single
>>>>> guest fail without all of them failing?
>>>> Think load balancing. Say 10 vservers, split them
>>>> so that 5 run on each host normally. If either host
>>>> goes down, the other one picks up the slack.
>>>> Everything runs slower, but at least it still runs.
>>> I think about the same considerations at the moment, planning
>>> a new setup.
>>> Why not make 2 DRBD shares, A and B, put half of the vserver
>>> guests on the A storage, unify, them, and then put the other
>>> half on the B share. All the vserver guests on the A DRBD
>>> share runs on the A-host, and like wise with the B host. In
>>> daily usage you have no open files from the B share on the A
>>> host, so all the memory would be unified. In case of a split
>>> brain you can keep the guests running, and once you get
>>> connection again easily resync the DRBD.
>>> In case of 1 vserver host failing then you can just start
>>> all the vserver guests in DRBD share A on the vserver host
>>> B. Yes that will not unify both groups of hosts, but that
>>> should only be until you get the A host up again.
>>> So, what do you think?

>> I still don't see the advantage of using DRBD for block-level
>> replication here. The extra complication of having to deal
>> with FS level fail-over doesn't seem to buy you anything
>> compared to the lsyncd mirroring setup.

> can you guide me to a good lsyncd howto?

> can lsyncd replicate ACL?
> Can it replicate non linux vserver guests?

you have non-linux vserver guests? :)
or non-linux-vserver guests?

best,
herbert

> (i'd rather have one sync system that does it all, than
> having multiple systems)

> JonB
Received on Fri Apr 15 16:36:25 2011

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