Author Archives: George Valentin Voina

DB2: (SQL Error: -30090) caused by XA access to a nickname to a federated database

By | February 8, 2017
1 Comment

In a setup having an enterprise application depending on a database instance where some tables are defined as nicknames to tables from a federated database, it can happen to get this very cryptic DB2 error. [12/10/15 18:06:54:895 IST] 00000073 SqlExceptionH Z org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions SQL Error: -4229, SQLState: null [12/10/15 18:06:54:903 IST] 00000073 SqlExceptionH Z org.hibernate.engine.jdbc.spi.SqlExceptionHelper… Read More »

#DRBD based disk replication of a production cluster to a remote site cluster on RHEL 6

By | May 26, 2017
2 Comments

1 General Considerations Our example enterprise applications run on a Linux Cluster with a shared cluster storage resource. Having this HA setup ensures that we have a high rate of service availability on the production site. To ensure that the disruption time in service of our enterprise application is minimal as possible the best solution… Read More »

Disable SSL3 in Glasshfish

By | May 26, 2017
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As we know there are big security concerns about the use of SSL3 so a lot of security audits are demanding it to be disabled in all applications that are exposed with a WEB GUI. Disabling SSL3 can be done via the admin console. First SSL is disabled individually on the HTTP listeners of your… Read More »

iSCSI SAN resources configuration as shared disks in a cluster environment, replicated also with DRBD

By | April 24, 2017
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The following configuration was created to use the iSCSI exported resources from a NetApp storage device as shared disk resources in a Linux cluster environment. The same resources are also replicated to a remote cluster using DRBD disk replication. The production environment contains four exported SAN resources which will be used as shared resources in… Read More »

DB2: Finding and adding indices

By | February 8, 2017
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DB2 has a very powerful tool (db2advice) to determine necessary indices for your DB2 database. Having a good index can have a very big boost in performance in any application. If working with high throughput systems it is crucial to have the right index. Note that my databse user is db2inst1 and database name MMS.… Read More »

DB2 Sqlcode: -964, Sqlstate: 57011 (transaction log for the database is full)

By | February 8, 2017
1 Comment

I got this error while doing some performance tests on a high volume system using DB2. This is the usual unintuitive error that IBM likes to give to the users 🙂 IN plain English this means that “The transaction log for the database is full.” This appears when you have to execute UPDATE or INSERT… Read More »

Windows 10 NIC teaming – disabled by MS for client SKU

By | October 21, 2017
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My Dell XPS 8700 desktop comes with a Realtek PCIe GBE Family Controller. By adding another 2 port Realtek PCIe GBE Family Controller I wanted to get a faster connection to the servers. Note that each of the HP Microserver servers has a 2Gbps connection obtained by NIC teaming the 2 port adapters in Linux.… Read More »

EdgeRouter : Dual WAN with Hair Pin

By | January 7, 2016
1 Comment

Starting with firmware version 1.4 EdgeRouter can be configured in a dual WAN setup using a very simple wizard. Then to configure some port forwarding rules to access the internal web server or VPNs there is a nice GUI setup window. Note that I experienced frequent switches between the main WAN and the backup WAN.… Read More »

EdgeRouter : Activate the DNS filtering of add servers

By | February 10, 2017
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Everybody hates Add Servers so all my PC and mobile browsers use AddBlock+, but still I do not want the extra traffic that is done even by using ad blockers. The best solution is to simply block from the EdgeRouter Ubiquiti Networks ERLite-3 EdgeRouter Lite the ad sites. The best guide for this is: EdgeMAX… Read More »

EdgeRouter : activate CLI root account

By | April 1, 2016
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To be able to do several CLI configurations administrator (root) account must be activated. By default EdgeRouter has this account disabled. It seems that even if is activated a firmware upgrade will revert it to the default configuration (disabled). To activate the root account follow the tutorial: EdgeMAX – What is the root account password?… Read More »