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#Mirroring

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Mirroring is an InterSystems technology for High Availability, Disaster Recovery and Database Backup and OLAP solutions.

Documentation.

Hi,

Can a Cache Mirror be used in the cloud ? (ie stand up a Primary and Backup member instances in a High Availability Cache Mirroring configuration)

I'm investigating the validity of this configuration, because I was of the understanding that this may not possible due to these cloud servers not (typically) having fixed ip addresses, which interferes with the Virtual IP settings for the mirror set.

Is this correct, and if there are workarounds (like Load Balancing ?) can I have details on how this should be configured ?

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Mikhail Khomenko · Oct 30, 2016
ISCAgent debug

Good day!
Is there an opportunity to debug the ISCAgent behaviour (in Linux)? ISCAgent uses /etc/iscagent/iscagent.conf as configuration file, but in docs I've found a description only for two parameters (port number and interface - http://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=...). Other parameters I can see by running /usr/local/etc/cachesys/ISCAgentCtrl status:

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Jon Astle · Nov 9, 2017
Detecting and managing failover

I have Ensemble/Healthshare running in a production environment which is setup with a mirror failover and an arbiter sitting between them.

In the event of a failover we have a number of connections that need stopping/monitoring and starting in a certain order.

Is there a programmatic way we can detect the failover and stop certain services and operations immediately and then start them up again in the required order, checking their connection state before starting the next connection.

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Hi, we have mirrored databases, now we have three nodes. Primary, backup, async. They are sync by journals and with some TB each node (expensive storage).

I would like to have a scenario where the two nodes (Primary and backup) have the same amount of messages (purge task of x days) , both as failover, but the asynchronous node should have more messaging, as much as the storage allows us. We want to use this node so provider can give support(search old messages), but not have databases in production that are so large that they are hardly consulted.

Any ideas?

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Hello,

I work on deploying IRIS inside Docker container. I really like %Installer class can automate many steps. I want to establish an ECP connection to a mirror database and then define a remote database on the application server. I have already seen we can create local database and namespace in %Installer. What code is needed to establish ECP connection?

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Joan Cruz · May 7, 2018
Information of Mirror servers

Hi

I'm using this query "Config.MapMirror.List" To get information of the list of servers that are in the mirror system.

I'd like to know how can I know which of the list is the primary and which is the failover or async member.

Is there a way to do it with this query? Is there another query to get this info?

Thanks a lot

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In System Administration | Configuration | System Configuration | Journal Settings there is a check box for Freeze on error.

From reading the documentation, it sounds like the choice to freeze on error is one of system availability vs system integrity.

Curious to know whether Ensemble users choose to freeze on error or not.

If you have a best practice recommendation based upon your experience or knowledge, that would be helpful information too.

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Hey everyone.

I have noticed that my backup mirror is warning that the MirrorDatabaseLatencyTime is having a bad time (time in ms is 3000, and warnvalue is 3000). While I look into what may be causing this latency between the two servers, I was considering if reducing the size of the journal files would improve this value in any way.

My assumption is that reducing the file size would mean that the frequency of the journal files being created would be increased, but the reduced size would mean that the transfer and application of each file would be reduced.

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Hi All!

I asked previously about the DR server in the cloud but actually, I'm curious about the backup server to use as analytics server more than for recovery in DR case.

There is a recommended practice to use an async mirror as a server for BI (InterSystems Analytics, DeepSee)

The question is if I have PRIMARY in the cloud (AWS, Google, Azure, etc) "how far" should async mirror member be placed? Same cloud, same private cloud or it doesn't matter at all for analytics purposes?

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In the context of IKO (Iris Kubernetes Operator) the question of Service not redirecting dynamically to the correct Pod is still pending.
In production this can be dangerous since an overload (or any other simpler problem) can cause you to change the main Pod and leave the application inoperable until we intervene.

Intersystems support warned that this is still an issue of IKO, but there are some possibilities that I am studying.

To explore an idea I had, I would like the help of this Forum to answer the following question:

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Hi All,

Our mirrored HealthShare environment has failed over a few times recently due to underlying infrastructure issues (that are being worked on and resolved).

In the HealthShare logs we are seeing:

10/06/22-00:54:35:925 (4736) 1 Journal Daemon has been inactive with I/O pending for 10 seconds:
gjrnoff=524741316,iocomplete=523852600,filecnt=1011,fail=0
10/06/22-00:54:55:086 (4736) 3 CP: Pausing users because Journal Daemon has not shown
signs of activity for 30 seconds. Users will resume if Journal Daemon is active again

My question is:

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ED Coder · Dec 5, 2018
Schema not appearing on Mirror

Hi, I updated the schema on our live node, but the change did not occur on the mirror server. Is there some setting that I need to enable? Everything else seems to be updating but the schema has not

Can you advice on what I could be missing or is this something that is known?

Regards,

Eric

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When I create a TASK on the Primary mirror member and Try to create the same TASK in the backup mirror member, It Gives me CSP Application error.

The TASK gets created in the Primary node without any errors and When creating in the Backup node it prompts the error.

It happens is IRIS and I didn't face this in CACHE.

Finally what I did is export the TASK in Primary and Imported in Backup.

Is this a feature of IRIS?

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Joan Cruz · Aug 2, 2016
Use of $ZUTIL(49) is deprecated

Hi all,

I'm using $ZUTIL(49) to get information of the databases I want to add to a mirror. This information is passed to ##class(SYS.Mirror).CatchupDB(plstPathDatabases) in order to Catchup all databases addes to a Mirror.

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Hi,

I'm trying to add a DR async member to a mirror but when I add this member I get this messages in the mirror monitor (on the DR member):

The message im talking about is the "missing Mirrored Databases report".

The only step I did was the " System Administration -> Configuration -> Mirror Settings -> Join as Async" an fill the blanks. Maybe Im skipping a step?

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Question
Rich Taylor · Aug 18, 2016
Read only Async mirror setup

I have setup an async reporting mirror member with Read only access. My problem is that if I try to do any sql reporting against that data I am getting errors. I am sure that this is because the DB is read only, but I had assumed that setting up a reporting mirror would handle this.

I there a setting or mapping I am missing?

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ISCAgent is automatically installed with Cache, runs as a service and can be configured to
start with the system. This is fine – but the complication comes when this is on VCS clusters with
Mirroring on. When installing a Single Instance of Cache in a Cluster, point number 2. Says “Create
a link from /usr/local/etc/cachesys to the shared disk. This forces the Caché registry and all
supporting files to be stored on the shared disk resource you have configured as part of the
service group.”

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Joao Palma · Mar 4, 2019
Missing Mirrored Database

Hi guys

I've added a new mirrored failover member to an existing one.

They are both Arbiter controlled.

When I do Add database to mirror on the primary I'm always getting an error. Missing Mirrored database.

I followed everything in the documentation and always get the same error.

I've copied the CACHE.dat file after umounting the database on both servers. then mounted them.

Could you help me out?

Kind Regards

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