Oracle Big Data Appliance X4-2: First impressions

The last 2 weeks we are lucky enough to have the Big Data Appliance (BDA) from Oracle in our lab/demo environment at VX Company and iRent. In this blog post i am trying to share my first experiences and some general observations. I am coming from an Oracle (Exadata) RDBMS background so i will probably reflect some of that experience on the BDA. The BDA we got here at is a starters rack which consists (more...)

Grid logging in 12.1.0.2

Most of the talk about Oracle’s release of 12.1.0.2 is about the InMemory feature, but more things have changed, for example some essential things about loggin in the Grid Infrastructure have changed. Normally in Oracle Grid Infrastructure logging for Grid components was done in $GI_HOME:

oracle@dm01db01(*gridinfra):/home/oracle> cd $ORACLE_HOME/log/`hostname -s`/
oracle@dm01db01(*gridinfra):/u01/app/12.1.0.2/grid/log/dm01db01>

There we have the main alert log for GI and several subdirectories for the GI binaries where they write (more...)

Inserts on HCC tables

There are already a lot of blogposts and presentations done about Hybrid Columnar Compression and i am adding one more blogpost to that list. Recently i was doing some small tests one HCC and noticed that that inserts on a HCC row didn’t got compressed and yes i was using direct path loads:

DBA@TEST1> create table hcc_me (text1 varchar2(4000)) compress for archive high;

Table created.

KJJ@TEST1> insert /*+ append */ into hcc_me select dbms_random.string('x',100)  (more...)

Cellcli can lie to you…

Yes that is true, i said it, cellcli can lie to you there are some special cases were the output of cellcli is not the reality and you should double check it’s output with your standard OS tools. So this the output if dcli calling cellcli on an Exadata rack from an client:

[root@dm01db01 ~]# dcli -g cell_group -l root cellcli -e list cell attributes cellsrvStatus,msStatus,rsStatus
dm01cel01: running       running         running
dm01cel02: running       running         running
dm01cel03:  (more...)

Rolling back a failed rootupgrade.sh CRS upgrade

Recently i was upgrading a half rack Exadata to Grid Infrastructure 11.2.0.4. for a customer who had 1 node removed from the cluster, at least so we thought. While doing the upgrade we ran rootupgrade.sh on the first 2 nodes without issues. Now when running the script on what supposed to be the 3rd and final node in the cluster, the rootupgrade.sh failed with the following error:

CRS-1119: Unable to  (more...)

Info about Exadata’s imageinfo and rpm’s

Recently we noticed that imageinfo was displaying the following information at a customers site. Imageinfo was not displaying data i suspected, so a quick little blogpost about what was going on there.

[root@dm01db01 ~]# dcli -g /opt/oracle.SupportTools/onecommand/dbs_group -l root "imageinfo | grep 'Image version'"
dm01db01: Image version: 11.2. (more...)

About cellcli calibrate

With cellcli you can run the calibrate command, this will measure the performance of your harddisks and flashcards. It will eventually report to you the throughput and amount of IOPS that was measured during the calibrate, it will also report to you which luns are not performing up to par.

(more...)

Exadata system stats and MBRC

Last year Oracle added a new functionality to dbms_stats.gather_system_stats, making it more Exadata aware and thus let the optimizer make choices that might result in offloading more often. See this blog post from Kerry Osborne about it, i made a small comment about the MBRC in it and i (more...)

Analyzing page allocation failures on Exadata

I have seen several clients who are struggling to decode page allocation failures on Exadata, in this post i will try to explain how to read the backtrace. The following is an anonymized client case where page allocation failures are leading up to a node reboot.

Jan 1 11:58:02 dm01db01  (more...)

Exadata V2 and CPU scaling

A while ago I was doing some bandwith and latency testing of infiniband interfaces on different Exadata configurations and ran into something that might be interesting for Exadata V2 owners out there. You can do some performance test on your IB stack using a set of tools that start with (more...)