software

Management

Under management, in the web site, we will cover the following topics :
the software which are related to keep a list of all your assets and to build your CMDB if you are an ITIL adict.
to keep an eye on what's going on among your system and to be warned at time when something not wanted happen.

Load balancing

Load-balancing, this is the capability to direct queries to a member of a server farm in turn.

This action can be simply done by using DNS Round-Robin, that's when you configure in a DNS more than one A record for the same name. So at each query to resolve this name, the DNS server will respond with a different IP address, cycling into the set of A records provided for this unique name.
But in this scenario, there are a lot of potential problems :

HA on filesystems

The RAID system, beeing hardware or software, will protect your local filesystems against disk failure. But when these filesystems are shared to other system, you need also to protect against failure of the host sharing the filesystem. This can be done by using a SAN and a cluster software that will mount and share again some SAN LUN's if a server failed.

But there are alternative solutions to the costly SAN. The OpenSource community offers you various kind of mechanisms to build highly-available filesystem.

Filesystem replication

Failover of database

When it comes to high-availability of databases, numerous strategies can be applied.

Do we need a complete active-active solution doing load-balancing ? Or do we have enough with a standby database ?
The technical implications behind these choices are totally different, also the reaction to outages will be different of course.

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