Smart Scans are part of what Kerry Osborne calls the ‘secret sauce’ of Exadata, and he’s right. Smart Scans can definitely improve throughput by using the various optimizations to reduce the amount of data read and the volume of data returned to the database servers. You really want to have them working on an Exadata machine. But how do you know they’re working? Let’s look at a couple ways to prove you have Smart Scans working for you.
The easiest way to prove you have a Smart Scan working (from the database server side) is to query the V$SQL view (more...)
This FF is a bit of a follow-up to the one I posted last week on PL/SQL skills and a comment made by Noons on how much knowledge you need to be an OakTable member.
I have a question to answer and I would appreciate other people’s opinion. Should there be more intro talks at conferences? If so, should the experts be giving them?
I am an OakTable member (and really quite worryingly proud about that) and I guess that means I know a lot about some aspects of Oracle. But also, and this is a key part of being (more...)
When the 184.108.40.206.1 release of the Exadata Storage Server software was released, I was a little excited. There were numerous oneoff patches for the previous release, 220.127.116.11.0, which was the first version to support the Exadata X3, writeback flashcache, run UEK on the X#-2 systems, etc. With that many large changes introduced in one version, it was likely to see some bugs in the .0 release. Fortunately, Oracle was quick to fix many of those issues, but it resulted in several separate patches to update the cellsrv software.
I was working with (more...)
1. It boggles my mind that some database technology companies still don’t view compression as a major issue. Compression directly affects storage and bandwidth usage alike — for all kinds of storage (potentially including RAM) and for all kinds of bandwidth (network, I/O, and potentially on-server).
Trading off less-than-maximal compression (more...)
Well, I’ve just finished pushing the last few bits into my suitcase for my trip to the US for the Rocky Mountain User Group Training Days 2013.
It is a few years since I went to the US for pleasure (3 years?) and much longer since I went there on a combined work/pleasure trip – as I HATE going through US immigration.
I was tempted into this trip when I met up with a fellow OakTable member Tim Gorman at the Slovenia User Group last October. Tim was a true gentleman throughout that conference (and this is not to (more...)
Recently one of my customers got a complaint from their DNS administrators, our Exadata’s are doing 40.000 DNS requests per minute. We like our DNS admins so we had a look into these request and what was causing them. I started with just firing up a tcpdump on one of the bonded client interfaces on a random compute node:
[root@dm01db01 ~]# tcpdump -i bondeth0 -s 0 port 53
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on bondeth0, link-type EN10MB (Ethernet), capture size 65535 bytes
15:41:04.937009 IP dm0101.domain.local.59868 > dnsserver01. (more...)
Well, it's been a really busy past few months, and I hate to admit it, but I've been neglecting this space more than anything. Despite having many different posts in the works, nothing is quite finished yet. I do have a little time to mention a few of my upcoming speaking events, though.
First, I'll be in Denver for the Rocky Mountain Oracle Users Group Training Days 2013, February 11-13. Enkitec has more than a few sessions during the conference, ranging from Exadata to Big Data to APEX. Check out the agenda for a full list. Also, we'll have an (more...)
I’ve worked on 24×7 systems for more than a decade, and I have a real dislike of downtime. For one, it can be a real pain to agree any downtime with the business, and while RAC can and does help when you do work in a rolling fashion, there is still risk.
The promise of online patching has been a long one, and it is only recently that I dipped my toe in the water with them. Unfortunately, they are not a panacea, and in this blog posting I’m going to share some of the downsides.
Of course not all (more...)
I have announced my webinar on Oracle ZFS Storage Appliance for Exadata Backup & Recovery in NYOUG DBA webinar series. You can download webinar slides and voice recod from NYOUG web site
In Friday December 14, 2012 at 12:00 PM -1:00 PM EDT I will be giving a webinar for NYOUG SIG with the following abstract
When it comes to the backup and recovery infrastructure of the Exadata Database Machine, conventional solutions often have only limited performance to keep up with Exadata throughput, whereas Oracle ZFS Storage Appliance can be configured as a very fast, capable, and easy-to-manage backup and recovery solution for any Exadata environment. In this session Husnu Sensoy will describe some of the configuration possibilities of the ZFS Storage Appliance to create a flexible backup and recovery environment for Exadata, (more...)
Hybrid Columnar Compression (HCC) is one of the Exadata features but lately Oracle has been pushing this featurei to other Oracle hardware like the ZFS Storage Appliance and Axiom Pillar Storage series. We recently got a ZFS Storage Appliance (ZFSSA) at VX Company, so we are now able to use HCC on the Oracle Database Appliance (ODA). To use HCC we need to create a tablespace with datafiles on a ZFS Storage Appliance, in order to de so we going to hookup our ODA using directNFS (dNFS). I am not going in the details of explaining dnfs in this blogpost, (more...)
Exadata offers many features to improve performance — Smart Scans, offloading, Infiniband internal network — but the one feature not often mentioned is the storage index. Designed to prevent Exadata from reading data blocks unnecessarily its purpose is sometimes not clearly explained, leading to confusion. So what is a storage index, where is it found and what does it do? Let’s see if we can answer those questions, and possibly a few more.
Exadata storage indexes are … indexes … but not in the usual bitmap/b-tree sense. You can’t use one to pinpoint the exact location of a particular record (more...)
I’ve been working a lot with graphing DB and OS metrics in R. I find it especially useful in Exadata POVs (proof of value) to gather and graph the oswatcher vmstat files for the compute nodes and iostat for the cells. For an example, take a look at this graph (PDF, 168 KB) of what [...]
In 2008 Oracle introduced Exadata, and data warehousing, business intelligence and OLTP applications have benefited from this integrated technology stack. Exadata is not like anything most DBAs have ever seen or managed; it’s a tuned combination of database server, storage server and private interconnects that truly can outperform commodity hardware configurations. Let’s take a peek inside Exadata and get a glimpse of what Oracle hath wrought.
An Exadata machine is more than just the parts that comprise it. In its smallest configuration the rack houses two database servers running Oracle Enterprise Linux, a storage server managing storage ‘cells’ (running its (more...)
With the announcement Exadata X3, Oracle has introduced a new feature called “FlashCache Writeback” to allow writes to cell Flash Cache (aka Exadata Smart FlashCache) in WriteBack mode. Earlier with WriteThrough mode, writes were not written to FlashCache, instead they were written directly to cell disks. Exadata software used to decide whether to cache these writes back into FlashCache or not. In WriteBack mode, writes are written to cell FlashCache and acknowledgement is given back to calling process as soon as data is written to flashcache. Exadata Server software de-stages the dirty writes in flashcache to spinning disks in the (more...)
Well, it's finally public, so we're able to openly talk about the new Exadata X3 systems. Looking back on my pre-openworld predictions, I was pretty close on a few things. I was correct on the database servers, which will have Xeon E5-2690 CPUs (8 core, 2.9GHz) with 128GB RAM upgradeable to 256GB. It looks like we won't get active/active Infiniband for a while, since the cards in there are staying the same. On the X3-8, the compute nodes are staying the same, for reasons detailed by Kevin Closson a few weeks ago. I also previously blogged about the (more...)