Hi Geert,

Doing something more intelligent and automatic to improve HA is something that has come up internally as well, not just for Security, but also the other auxiliary / default databases. It's something we'd like to do better on.

There is a little bit of complexity around which hosts handle the replica forests in different deployment situations. In a private data center, it might not matter which host handles the replica forests since all the hosts are in the same rack. For AWS, you want to put them in a different availability zone.

We added a "zone" descriptor in ML7, and that seems like a good input for us to use in deciding which hosts should handle the replica forests. On AWS, it gets set automatically for you. In a private data center, you'd need to manually set it according to your topology (e.g. which rack it's in).

Ideally, I'd like these replica forests to just quietly happen when a cluster is initially formed, and users can adjust to their liking later if desired.

Wayne.



On 03/18/2014 02:04 PM, Geert Josten wrote:

Yes and no..

By default installation, all hosts start with their own Security database (, and Modules, and Schemas, and Triggers, and Apps, etc). But as soon as they join an existing cluster, they seem to forget they have forests, and databases of their own.

The issue is of course that you cannot have two databases with the same name, so there is a logical explanation for why it currently is this way. But I am just wondering whether it is possible to make it slightly smarter..

I am only thinking about the Security database, just because it is such a vital database..

Cheers

*Van:*[email protected] [mailto:[email protected]] *Namens *David Lee
*Verzonden:* dinsdag 18 maart 2014 21:31
*Aan:* MarkLogic Developer Discussion
*Onderwerp:* Re: [MarkLogic Dev General] Failed over Security Database

" Unless someone deliberately messed up, all hosts have a Security database."

Unless you explicitly set it up differently, the Security database that all hosts have

in a cluster is *the same database* (A single forest on the first host installed in the cluster).

**

**

*From:*[email protected] <mailto:[email protected]> [mailto:[email protected]] *On Behalf Of *Geert Josten
*Sent:* Tuesday, March 18, 2014 4:19 PM
*To:* 'MarkLogic Developer Discussion'
*Subject:* Re: [MarkLogic Dev General] Failed over Security Database

Nice.. :)

I'm a little surprised though that Security needs explicit measure to make it fail over in a cluster. It is pretty vital. Unless someone deliberately messed up, all hosts have a Security database. Couldn't it replicate that database across all other hosts by default, just like all other server configs are being shared automatically?

Cheers

*Van:*[email protected] <mailto:[email protected]> [mailto:[email protected]] *Namens *Danny Sokolsky
*Verzonden:* dinsdag 18 maart 2014 20:07
*Aan:* MarkLogic Developer Discussion
*Onderwerp:* Re: [MarkLogic Dev General] Failed over Security Database

And as my colleague Dave pointed out to me, if you are using 7, you can do this same task easier by adding a new forest (with a public data directory) and retiring the old:

http://docs.marklogic.com/guide/admin/database-rebalancing#id_23094

Similarly, you can use tiered storage to migrate the forest.

-Danny

*From:*[email protected] <mailto:[email protected]> [mailto:[email protected]] *On Behalf Of *Danny Sokolsky
*Sent:* Monday, March 17, 2014 11:01 PM
*To:* MarkLogic Developer Discussion
*Subject:* Re: [MarkLogic Dev General] Failed over Security Database

In order to set up failover on a forest, it must be in a directory other than the default directory. The default directory (/opt/MarkLogic/Forests on linux, for example) is known as a "private directory."

For the procedure to move a forest to a public directory, see this section of the doc:

http://docs.marklogic.com/guide/cluster/config-both-failover#id_57935

and this section:

http://docs.marklogic.com/guide/cluster/config-both-failover#id_74893

Once you do that, you should be able to set up failover on that forest.

-Danny

------------------------------------------------------------------------

*From:*[email protected] <mailto:[email protected]> [[email protected]] on behalf of Abhishek53 S [[email protected]]
*Sent:* Monday, March 17, 2014 6:04 PM
*To:* MarkLogic Developer Discussion
*Subject:* [MarkLogic Dev General] Failed over Security Database


Hi,

I am trying rename and add forest-failover to the default "Security" database and getting exception

Invalid input: Failover is not allowed for private forest: Security


Please advise
Abhishek Srivastav
Tata Consultancy Services
Mailto: [email protected] <mailto:[email protected]>
Website: http://www.tcs.com
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