Milestone XProtect Advanced VMS 2014 Manuel d'utilisateur télécharger pdf (Page 226)

Milestone XProtect

Advanced

VMS 2014

Administrator's Manual

www.milestonesys.com

226

Feature configuration

About failover recording server functionality

 A failover recording server checks the state of relevant recording servers every single 0.5

seconds. If a recording server does not reply within 2 seconds, the recording server is

considered unavailable and the failover recording server takes over.

 A regular failover recording server takes over for the recording server that has become

unavailable after five seconds plus the time it takes for the failover recording server's

Recording Server service to start and the time it takes to connect to the cameras. In contrast, a

hot standby recording server takes over faster because the Recording Server service is

already running with the correct configuration and only has to start its cameras to deliver

feeds. During the start up period, you can neither store recordings nor view live video from

affected cameras.

 When a recording server becomes available again, it automatically takes over from the failover

or hot standby recording server. Recordings stored by the failover or hot standby recording

server are automatically merged into the standard recording server's databases. How long the

merging process takes depends on the amount of recordings, on network capacity and more.

During the merging process, you cannot browse recordings from the period during which the

failover or hot standby recording server took over.

 If a failover recording server must take over from another recording server during the merging

process in a regular failover recording server setup, it postpones the merging process with

recording server A, and takes over from recording server B. When recording server B becomes

available again, the regular failover recording server takes up the merging process with

recording server A, after which it begins merging with recording server B.

In a hot standby setup, a hot standby server cannot take over for another recording server

because it can only be hot standby for a single recording server. But if that recording server

fails again, the hot standby takes over again and keeps the recordings from the previous

period. The recording server keeps recordings until they are merged back to the primary

recorder or until the failover recording server runs out of disk space.

 A failover solution does not provide complete redundancy. It can only serve as a reliable way

of minimizing the downtime. If a recording server becomes available again, the Failover Server

service makes sure that the recording server is ready to store recordings again. Only then is

the responsibility for storing recordings handed back to the standard recording server. So, a

loss of recordings at this stage of the process is very unlikely.

 Client users hardly notice that a failover recording server is taking over. A short break occurs,

usually only for a few seconds, when the failover recording server takes over. During this

break, users cannot access video from the affected recording server. Client users can resume

viewing live video as soon as the failover recording server has taken over. Because recent

recordings are stored on the failover recording server, they can play back recordings from after

the failover recording server took over. Clients cannot play back older recordings stored only

on the affected recording server until that recording server is functioning again and has taken

over from the failover recording server. You cannot access archived recordings. When the

recording server is functioning again, a merging process takes place during which failover

recordings are merged back into the recording server's database. During this process, you

cannot play back recordings from the period during which the failover recording server took

over.

 In a regular failover setup, setting up one failover recording server as backup for another

failover recording server is not necessary. This is because you do not allocate particular

failover recording servers to take over from a standard recording server. Instead, you allocate

1 2 ... 221 222 223 224 225 226 227 228 229 230 231 ... 296 297

Milestone XProtect Advanced VMS 2014 Manuel d'utilisateur Page 226

Commentaires sur ces manuels

Milestone XProtect Advanced VMS 2014 Manuel d'utilisateur Page 226

Commentaires sur ces manuels

Produits connexes et manuels pour Logiciel Milestone XProtect Advanced VMS 2014