Re: [CentOS] how to increase DNS reliability?

2019-07-28 Thread Giles Coochey


On 26/07/2019 17:35, Nataraj wrote:


If you administer the secondary slave servers, there is no reason not to
use a very large number, 30 days or more for the SOA expiration.  Only
reason to use a lower number would be if you don't have control over the
slave servers and don't want to have old zone files that you can't update.

Another alternative, which many people did for years in the early days
when zone transfers were unreliable, is to use a script which replicates
the entire DNS configuration to the secondaries and then run all the
servers as primary masters.  If the script is written cleanly, you can
then edit the zone on any server and rsync it to the other servers.
Main thing is to prevent multiple people applying updates simultaneously.

Nataraj
PowerDNS supports MySQL backends for the zone files, so one way that 
they can work is in Native mode, as an alternative to Master / Slave, in 
which the replication and information resilience is handled by the 
backend (e.g. a MySQL cluster), and the servers just read the zone from 
the database, with no need to perform zone transfers at all. The expire 
timer in the SOA record then becomes pretty defunct, although if you 
export your zones to non-PowerDNS servers, e.g. bind, then they take effect.

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Re: [CentOS] CentOS 8 partiitioning for reliability

2019-07-28 Thread Kenneth Porter

--On Thursday, July 25, 2019 4:21 PM +0200 hw  wrote:


In any case, get two 147GB disks to install the system on and use some
RAID mirror setup to create two logical volumes.  That separates system
from data and leaves you two spares for when a disk fails.


I'm considering buying a couple 512GB SSDs to run in a mirror as the boot 
drive and use all the regular drives in hardware RAID 6 as /home (including 
IMAP email and Samba shares). I'm guessing I should put swap on the 
spindles?



You may want to take out some of the memory and check power consumption
since more memory might consume more power, and you don't need that much.


Good idea. I'll probably cut it down to 32 GB, mostly for use by 
SpamAssassin and ClamAV.


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