I thought I would raise some thinking matter and opinions on this after recently attending the Oracle/Sun “Oracle Extreme Performance Data Warehousing” event, this event included a morning of content and slideware highlighting the inhierent architectural benefits of Oracle Exadata 2.0 and how this can be used to improve performance of processing important data hosted on DW’s and OLTP. Additional to the Exadata content of the presentation I was also interested in going to this event to get a vibe on what the future of SUN will now look like with Oracle now completely acquiring SUN.
Since Version 1.0 Exadata (HP Version) I have learnt quite a large proportion about Exadata’s value prop and technical benefits it offers via the various industry coverage and marketing pushes from Oracle, I also have heard great things about it from a #storagebeers founder and brain in a jar @ianhf who absolutely raves (in a grumpy way of course) on the levels of performance that he is experiencing with data warehouses on the kit.
Following the full SUN acquisition Exadata v2.0 Database Machine has surfaced with a large push as this being the IBM P series killer. This now seems to be being pushed more than anything by Oracle and I went along to find out why this is and what differentiates this from both alternative high end based infrastructures and how something like Exadata pitches its benefits above and over SAN.
I will give an overview of whats under the hood and then give you my view on what I think of Exadata and what I think its pros and cons are for datacentre environments.
Here is a brief summary of some of the key tech features highlighted from the slideware;
- Oracle Exadata Smart Flash Cache – Exadata v2.0 utilises this technology and is a differentiator to other conventional DB server/storage infrastructure. FaC In Exadata puts “Hot data” which was typically on slower external disk on localised flash, this removes the associated bottleneck when excessive data processing occurs between conventional Server/SAN disk,
- Infiniband Connectivity - “Exadata cells” or in simplistic terms the Exadata disk shelves use IB to connect between Disk and Diskshelve, this is configured within a grid format with Oracle RAC so scales data across Cells,
- Utilises cost effective storage mediums – I was led to believe it used Flash as the storage medium, when in actual fact it dosn’t and in fact doesn’t need to due to Flash Cache, it uses SAS/SATA disks to store older less frequently accessed Data and utilises the Flash cache to store “hot’ tables that are in high demand from the DB queries,
- Scalable building block design - Entry level begins with single shelves and can scale up as and when required, before attending I was also led to believe by the in your face marketing tactics of Mr Ellison that it was a One rack only solution, when in actual fact you can start with one cell and scale up as and when required,
The above is a small list of technical detail summary, and to be honest it may not be completely right or in complete detail, there is a whole plethora of technical benefits that lie within an Exadata, during the event you wasn’t able to kick the tyres on the Exadata, it was at arms length mainly due to the target audience being Data related IT folk and business leaders. Figure 1 is my high level view of where data relevant data resides and where I/O requests flow within the Exadata stack;
Exadata design principles
Oracle quote that the required Infrastructure “plumbing” for an Exadata setup is pure consolidation in a box when compared to typical end to end FC environments, and this is quite apparent, with One rack providing TB’s of storage with 10x more quoted performance gain over conventional infrastructure it quite firmly backs this statement up. Exadata offers a simplistic built from factory set of Infrastructure building blocks which eliminates the complexity and excessive design and planning work to implement SAN based environments.
Exadata my view
So here is my take on Exadata….First statement I make is like most other Oracle product offerings they have the sales tactic of penetrating into a business via top down approach from the C levels in organisations, on the technical front Infrastructure Architects very rarely get to know a product like Exadata, RAC, ASM etc so they push into Organisations is via the Database Admin/Architect. Exadata is no exception to this statement, I confidently say this based on the lack of hands on or “kick of tyre” approach at the Exadata event, also there seems to be a plethora of system integrators who you can engage more with to find out (thanks but no thanks).
Exadata is not sexy, its not tweakable as its already tweaked, it just sits in a rack in your datacentre and number crunches (apparently very quickly). Something the mainframe has done for years and something that has made IBM what they are today. Exadata is not a magic peice of hardware, it is a combination of common sense architecture design and well thought out integration tuning with the all important workload being catered for of the Oracle DB.
I relate how Exadata has been engineered to Graeme Obree and his historic Washing Machine bike , this was a record breaking winning bike built from ideas and unconventional parts, with this being so relative to Exadata the Features I highlighted within the Technical overview are nothing new and mean you could potentially build your own system which achieves similar results, remember;
- You can buy PCI based Flashcache cards from organisations like FusionIO and use this with Oracle 11g
- Infiniband switches are readily available and you can implement this to achieve similar levels of performance
- Working with your data teams you can likely achieve similar performance gains by incorporating hardware initiatives within Exadata
Exadata is not going to go away and Exadata v1.0 proved this, it apparently was a flop in the market place, so much of a flop Oracle released another one! Importantly I beleive an advantage is its not using heavily developed ASICS or onboard array software and hardware kit and the software has already been developed or is commoditised, something which is a benefit against SAN Array vendors who have invested in customised array software and monolithic arrays. Therfore I expect Oracle to keep banging the drum with Exadata.
Apologies for the long post, I tried to keep it to bare minimum, Exadata although small on footprint really is a finely tuned beast offers people the chance to move away from complex FC based environments for DW and OLTP without sacrificing performance. Importantly thought you must be conscious of the benefits of a SAN that get left behind such as Replication, Cloning, Management ease and many more.
Prediction is that environments for large DW will be the breadwinner for Oracle, and also the breadwinner when put up against Netezza and other DW specialists when in an RFP. For OLTP workloads however there is a slim chance that Exadata would go any further than the Storage teams in an organisation. SAN’s offer benefits externally to just the LUN that is presented, I’ve not covered DR and Continuity in Exadata, that’s a whole new blog post on its own, however SAN will predominantly win on this account and I may blog about this sometime in the near future.