[Samba] about samba failover

[Davor Vusir]

Den 29 jun 2014 01:38 skrev <me at electronico.nc>:
>
> Le 29/06/2014 06:50, Davor Vusir a écrit :
>
>> 2014-06-28 20:16 GMT+02:00 steve <steve at steve-ss.com>:
>>>
>>> On Sat, 2014-06-28 at 20:02 +0200, Davor Vusir wrote:
>>>
>>>> Never the less, domain based DFS works. Thanks to Garming, if I recall
>>>> correctly.
>>>
>>> Hi
>>> That's exactly what we want. Two domain file servers carry the same
>>> share. One goes down, there's still another left with the same share.
>>>
>>> Can you point us at a howto?
>>> Thanks,
>>> Steve
>>>
>>>
>> Hi!
>>
>> I haven't found a howto. If you can't Explore to
>> \\example.org\netlogon, I suggest you revert to Ubuntu 12.04 for
>> starters. :)
>>
>> According to the documentation
>> (https://www.samba.org/samba/docs/man/Samba-HOWTO-Collection/msdfs.html),
>> it is not possible in my opinion. At least not with automatic
>> failover. Because there is not enough information embedded in Sambas
>> implementation that informs the (Windows) client which server is to
>> prioritize and which is secondary and for how long this information is
>> valid. You can create links to several shares but you can't determine
>> which server the client will connect to (if it does not connect
>> alphabetacally(?)). If client A connects to server A the first time,
>> and client B connects to server B, you have to implement two-way
>> synchronization. There is no way to determine if the opposite occurs
>> at the next logon. The documentation fails to tell.
>>
>> The only thing you know is that domainbased DFS is possible. The
>> availability solution is for you to decide.
>>
>> I think it boils down to a solution with one (1) link to either a cold
>> stand-by server or a hot stand-by server(cluster) of some sort.
>>
>> If you choose the cold stand-by solution, you'll have to 'relink' to
>> the stand-by server manually in case of server crash. Does rsync copy
>> open files? How often is enough? Every five minutes? Or is inotify
>> (
http://www.kutukupret.com/2011/06/28/postfix-one-way-maildir-replication-backup-using-inotify-and-rsync/
)
>> good enough?
>>
>> If you choose the hot stand-by solution, I think DRBD will be
satisfactory.
>
> This is what my original question was about : RAID1 DRDB over network
>
http://blog.remibergsma.com/2012/09/09/building-a-redundant-pair-of-linux-storage-servers-using-drbd-and-heartbeat/
> I actually use this with 2 xen servers 10.10.20.2 and 10.10.20.3
> It creates a virtual ip 10.10.20.1 that holds the NFS whatever server is
on (with server1 prefered).
> Servers are connected through a direct ethernet link via Gigabit NICs
(that is used for the HA communication) and a 20G RAID1 array is actually
used to store common files between servers (dhcpd.conf, bind9 files) for
basic HA functions.
> I was thinking to use another network RAID1 array for Samba files but
haven't tried it right now.
> I'll let you know, but I now feel confident about the data integrity
(RAID1).
> Nicolas
>
Sorry for the elaborated non-related discussion. I hope it gave you
something though.

Looking forward to read the successtory.

Good luck
Davor

>>
>> With the first solution you will loose data/information. The second
>> guaranties consistency.
>>
>> The trick is one link to one server. High avaliability not included.
>>
>> Regards
>> Davor
>
>
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