CSM does not show single failed PPRC path in overview console

Thanks. That's a very interesting idea. Will have to think how best to do something like that. With that said, I did understand your point on performance, but my previous point is that CSM is not a performance monitor for you application data. If you want performance monitoring then Spectrum Control or OMEGAMON are designed to cover that, so that in the event, that you lost enough bandwidth such that it affects your application performance, you can be alerted immediately. Those products will help track the performance over time as well.

But I understand your concern. Let me see what we can do in CSM. While we can't monitor the performance maybe there's something like you suggested...some threshold support we can implement that customers can tune so that if they have performance monitored by another product they can disable it or lower it. thanks for the valuable feeback.

Hello,

thank you very much for your statement. Assuming that I got your point but I still do not agree!

What you have not considered is performance and the way how an organization is working. We recently had another link failure and got some messages for logical errors per mail but we (SYSPROG group) has limited shift. The operating is responsible and for them looking ta the GUI page everything was ok, eveything was green. So, they were not able to recognize the problem.

If you decide to implement 4 PPRC links to the other datacenter then this was also because of performance. If you loose one path you loose 25% of your performance and eveything is shown green in the GUI. Not ok for us.

What about if you think it to display as a quorum on the first page with configurable thresholds. For this you need only one additional line to display. For example if you have 400 logical pathes and loose one link you receive 100 messages. Ok, that is much. But what about to calculate a quorum? In this case 75% of the pathes are available and my pre-defined thresholds are <100 and <75 and <50. So, you have some different states for warning 1 <100% and warning2 <75% and critical <50%. Only as example.

What dou you think?
br!
Bernd

Thanks for the additional information. However, that still doesn't quite give me what I think I need. The votes for this RFE seem to be rising quickly so if there are others looking for this functionality, please comment on your preferences and personal scenarios.

Can you explain more what you mean by the fact that the 1 out of the 4 paths lead to "path problems"?

The reason everything in CSM showed green is because....it was green. CSM focus only on the replication and the DR aspect of the solution. CSM does not monitor performance. When multiple paths are setup between storage systems for replication the storage system will use those paths to balance the workload of the replication as well as to provide redundancy. It is quite possible for 3 out of 4 paths to be done with zero performance or application impact. Should the session or environment really show red if the replication is still running...there's no performance impact....the session is recoverable....and there would be no issues recovering a consistent set of data in the event of a disaster?

In the event that any of those is in a bad state, the overview would be lit up as well as the navigator. And events will be thrown if setup either through SNMP or email.

If you or the customer feel that we should show red despite all the above being in a good state, any suggestions on how to do that without causing unnecessary panic?

Some background information to probably understand the situation and request better: Alte Leipziger is a new CSM user after years of using own scripts for failover etc. The environment is a simple two-site MM without Hyperswap yet. But HS is planned to be added soon. The trigger for this RFE was a recent PPRC link failure (one out of four) which led to path problems.
I understand the decision to not display path (error) information in the overview given the huge number of possible paths.
On the other hand I understand the client's position to find it irritating that the overview shows everything green while path (and link) errors exist.
If path failure information can't be added, maybe s.th. can be done at the LINK level (I know this might be difficult, because it's physics where CSM has no control...)?

PS: we've informed Bernd about the alert possibilities and he's looking at it now.

Thanks for the RFE. It is not uncommon for there to be path errors in a customer configuration given the possible existence of 100s of logical paths across all the possible LSS pairings. Because of this we decided not to display the paths status on the overview panel, nor provide an icon for it on the navigator as we do for session and storage system connections. If we did, in most customer environments we found that this would be showing red constantly and not much help. In addition, the paths themselves that are listed may or may not be tied to a session on the CSM server. So it is possible that we'd show red for paths that aren't currently being used by anything in CSM.

With that said, there are some features in CSM that would help to alert you that something is wrong in the environment due to path issues.
1) In Global Mirror environments, you can define a Warning/Severe threshold alert. If the loss of a path results in lower bandwidth, then the RPO for the session would increase and if it passes the thresholds the session will go Warning/Severe and send an alert

2) In a recent release CSM added a change that would make a session go into a Warning state with an alert when the session was only created with, or has gone down to a single path between source and target LSSs. With only a single path there is no redundancy and so CSM will alert the customer to this even if the single path has not resulted in any application impact

3) There are SNMP and email events for pathing changes seen by CSM. These can be caught and handled with automation to alert you when the event is related to paths that may affect your environment. https://www.ibm.com/support/knowledgecenter/SSESK4_6.2.11/com.ibm.storage.csm.help.doc/frg_r_snmp_config_change.html

4) Any event that would result in the inability to fully recover the session at the remote site will lead to a Severe status and/or alert. The loss of a single path when other paths still exist, will not prevent recovery at the remote site and as such other factors may be better used to determine that something is wrong.

In addition to the above. There are performance monitoring products such as OMEGAMON or Spectrum Control that can help you monitor the actual application performance so that you're alerted to any conditions that may be due to the loss of paths.

I assume that you're aware of most of the above features though and are still requesting the change? If so, can you be a little more specific on what you'd like to see? For example:
Would you want it to show red on the overview panel if ANY path is in an error state?
Do you want the Navigator to also display a red icon if ANY path is in an error state?
Do you want to see the count of paths in the various states similar to what we show for the sessions on the overview?
Anything you can think to help differentiate known error paths to ones that are new and would cause you concern?