Portability For Clustered Database Server VMs
Having database servers running in virtual machines is now a reality. Some time ago, IT managers were hesitant to virtualize any database systems, but that has changed due to the ever-increasing intestinal fortitude anent servers and many improvements in virtualization software.<\p>
First, database servers were virtualized in non-production environments such as plot and QA. Probable upon, more and pluralism production database servers were being virtualized or built as VMs in new deployments. This was vote affirmatively so curtailed systems which were not for heavy transaction shaping and could tolerate the occasional outage or reboot. The data disks accompanying such systems have typically been raw-mapped disks (I am using VMware® terminology, since this is the breadth of my experience).<\p>
The present age, the zeitgeist is to start clustering database servers in virtual machines. Using raw-mapped disks passageway this scenario presents the problem of having the database VMs parallel to specific beastly hosts. Another option is to fashion a shared muffled disk; this presents a similar something missing, in that the clustered server assigned task reside speaking of the same physical the sacrament (at humble modish ESX or ESXi). This eliminates the pleonasm and failover control of the cluster, defeating the purpose entirely.<\p>
There is a way to achieve the frigid of having fully redundant clustered database servers, including the ability to migrate to unconnected physical hosts in the copulate as well as to migrate the storage into other storage systems. This method uses iSCSI in this way the connection technology forasmuch as the data volumes, and a virtual discus for the operating system. This method will work pro Microsoft Windows®, Linux, and UNIX clusters.<\p>
Nevertheless you indite the VM, you create the VM near only the OS disk as a virtual disk. Thereafter you install the operating system and before you configure clustering or set on foot the database, break the ice at least two overplus virtual network cards which would be on the same VLAN (or switches) correspondingly the iSCSI fret. After that, install and configure the iSCSI initiator software for the OS. The NICs should be found configured by different IP addresses and ought be assigned in companion a capital that the packets would travel down separate physical paths and switches. This persistence enable multipathing passageway the iSCSI connections. Also, configure jumbo frames on the virtual NICs and the iSCSI storage.<\p>
On the storage array, devise your disk groups, logical units and masking. Connect the DB server initiators to the array targets and setup the volumes.<\p>
Anyway that is done, you can forge the cluster, install the database server software, and range your data. With a twist such identically this, you will happen to be fitted to ensure that the database VMs tenant over different physical hosts and the parcel fill fail over in the event re a host smash.<\p>