Mike Ault's thoughts on various topics, Oracle related and not. Note: I reserve the right to delete comments that are not contributing to the overall theme of the BLOG or are insulting or demeaning to anyone. The posts on this blog are provided “as is” with no warranties and confer no rights. The opinions expressed on this site are mine and mine alone, and do not necessarily represent those of my employer.

Monday, September 29, 2008

Oracle's Data(Warehouse)base Machine

I just got back from OOW08, my wife and I tagged a couple of days in Napa, California onto the conference for our 35st anniversary so I am still getting back into the swing of things.

The biggest news at the conference was Larry Ellison’s announcement of the Exadata storage concept and the Oracle Database Machine both developed jointly with HP. These new storage and database devices offer up to 168 terabytes of raw storage with 368 gigabytes of caching and 64 main CPUs in 8 stacked DL 360 G5 servers and each Exadata unit has a HP Proliant DL 180 G5 with dual quadcore CPUs, 8 gigabytes of memory and 12 SAS 300 GB or SATA 1 terabyte drives. The entire HP Oracle Database Machine contains 14 Exadata blocks and 8 – dual quadcore servers in a full configuration. The Exadata blocks can be purchased separately. There are 4-24 port Infiniband switches provided in the Database Machine. The entire device provides a throughput of 10.5 (SATA) to 14 (SAS) GB/second.

Now, each Exadata block can only provide 1 terabyte if the 300 GB drives are utilized and 3.3 terabytes if the 1 terabyte drives are used unless Oracle compression is also used. This space calculation (from Oracle documentation) is based on mirroring of all the drives and subtracting space for logs, undo and temp space. The usual “your mileage may vary” warning applies to this available space. ASM with what appears to be high redundancy storage is being used to manage the drives. So while raw storage appears to be 3.3 TB to 12 TB the actual space that ends up being usable is only 1/3 of those amounts. Each Exadata has 2 – 20 Gigabit Infiniband interfaces. However, the blocks can only support 1 GB per second of output with the SAS configuration and 750 MB per second in the SATA configuration.

The Oracle Database Machine was actually designed for large data warehouses but Larry assured us we could use it for OLTP applications as well. Performance improvements of 10X to 50X if you move your application to the Database Machine are promised. This dramatic improvement over existing data warehouse systems is provided through placing an Oracle provided parallel processing engine on each Exadata building block so instead of passing data blocks, results are returned. How the latency of the drives is being defeated wasn’t fully explained.

The HP Oracle Database Machine must run Oracle11g,, RAC and Linux and each Exadata block must have the new Oracle 11g parallel query engine installed. So in a full configuration you are on the tab for a 64 CPU Oracle and RAC license and 112 Oracle parallel query licenses (assuming it is per CPU, if it is per Exadata block then it will be 14) as well as any Grid control licenses you may need. The base cost of the full Database Machine is around $650K which seems quite a bargain for 14-46 terabytes of usable storage and a 64 processor stack, however, you will also need over a million dollars in licenses even with aggressive reductions from your sales representative.

The HP-Oracle Database Machine only works with Oracle databases (just thought I should throw that in.)

Whew! The HP-Oracle database Machine offers quite an impressive array of facts, figures, promises and price tags. It will be interesting to see how this all sorts out over the coming months. Will there be enough profit in the HP-Oracle Database Machine to keep HP interested? Or is this another network computer? For those too young to remember Larry’s last hardware foray was the Network Computer, a device that would replace all the desktops and centralize application and data storage, it failed. [Note: don’t forget about Pillar Data another Ellision investment that would seem to be hurt by this announcement]. I believe this system is designed to help Oracle protect turf from Netezza and promote growth in the analytics market. Targeting the product to OLTP environments is just sloppy marketing as the system will not offer the latency needed in real OLTP transaction intensive shops. These applications do not need parallel queries, they need low latency database writes and reads.

So for nearly 2 million dollars (licenses plus hardware) you get a dedicated Oracle server in a rack with 64 CPUs of central processing and 46 terabytes of usable storage managed by 112 block resident CPUs and a wee bit less than 224 gigabytes of cache area (168 gigabytes of cache were promised after processing overhead was subtracted). However, you must throw away your existing infrastructure, upgrade to Oracle11g and marry your future to the HP Oracle Database Machine to do so.

What might be an alternative? Well, how about keeping your existing hardware, keep your existing licenses, and just purchase solid state disks to supplement your existing technology stack? For that same amount of money you will shortly be able to get the same usable capacity of Texas Memory Systems RamSan devices. By my estimates that will give you 600,000 IOPS, 9 GB/sec bandwidth (using fibre Fibre Channel , more withor Infiniband), 48 terabytes of non-volatile flash storage[S1] , 384 GB of DDR cache and a speed up of 10-50X depending on the query (based on tests against the TPCH data set using disks and the equivalent Ram-San SSD configuration). More importantly, this performance can be delivered with sub-millisecond response time. At Oracle World I was presenting on the importance of latency to Oracle databases. The Exadata is massive and offers great bandwidth but will have nearly awful disk access tedencies due to the massive and slow disk drives included in the system.

Of course, if you don’t need 48 terabytes you can purchase Ram-San SSD technology from 32 gigabytes up to whatever you actually need. Ram-San SSD technology works with all Oracle versions and requires no special licensing or changes to your system. Ram-San uses fibre channel or Infiniband for connection to your infrastructure and looks identical to a disk drive once configured (it takes about 10 minutes.)

Oh, and the Ram-San doesn’t care if you are on Oracle, SQL Server, MySQL, or cousin Joe’s Ozark Mountain special database.

So let’s recap:

Purchase the complex, tied to Oracle with a golden chain, HP-Oracle Database Machine and end up throwing away your existing technology stack, and spend up to 2 million dollars for the privilege, for a speed up of 10x to 50x on data warehouse type queries.


Purchase just as much Ram-San SSD technology as you need ($43K base price for 32 GB mirrored), keep your existing hardware and license structure (or possibly reduce it) and get a 10x to 50x speed up on data warehouse type queries, with the freedom to change databases as you need to.

Call me simple, but I think I see the proper choice.

[S1]Note that the 8TB systems are projected to have 1.5GB/second of bandwidth sustained reads or writes (to Flash). This can be accomplished with four 4Gbit FC ports or two 4x IB ports per unit.

Tuesday, September 16, 2008

Is there a DBA in the House?

No, I wasn’t recently at a theater that needed an emergency restart of the database for the show to go on. However I do watch a TV show called House. For those who haven’t seen the program House it is about an acerbic, disabled, pain pill addicted Doctor who just happens to be a genius diagnostician. Think of an anti-Marcus Welby (for those who remember the show Marcus Welby M.D.) Anyway, in each episode Doctor House and his team solve a medical problem by looking at the facts and applying logic, common sense and luck. Doctor House also has one rule, “Everyone Lies” and of course in each episode the pivotal point occurs when they find the lie that is obscuring the true source of the problem.

All of the problem solving that occurs on House reminds me of trouble shooting in the Oracle world. In many cases there are a number of symptoms with database problems and some of them are contradictory just as with problems in the human health areas. Oh, and everybody lies. “No, there weren’t any changes”, “No, nothing is different between these two test runs”, ”Yes, we used the same data/transactions/parameters”.

In almost every episode of House they go through at least three different “cures” before they find the real problem and solution. Many times in the Oracle universe we apply a fix for a problem, only to find it wasn’t really the issue, or, in fixing it we transfer the problem to another area of the database. Another similarity is that many times House and his team will take a shotgun approach when there isn’t a clear solution, applying two or more “cures” at the same time, much like a DBA will apply multiple fixes in a single pass, thus not really knowing what was fixed but just breathing a sigh of relief when performance improves.

I think the character portrayed as Dr. House would make a great DBA, but somehow I can’t see folks glued to their TV screens hoping that next index will fix the query…

Thursday, September 04, 2008

SSD is Green Technology

In a recent research project I compared the energy consumption of SSD based technology to IOPS equivalent disk based fibre attached SAN systems. As you can well imagine the SSD technology was much more space efficient, required less cooling and of course less electricity while providing faster data access.

But just how much can be saved? In comparisons to state of the art disk based systems (sorry, I can’t mention the company we compared to) at 25K IOPS, 50K IOPS and 100K IOPS with redundancy, SSD based technology saved from a low of $27K per year at 6 terabytes of storage and 25K IOPS to a high of $120K per year at 100K IOPS and 2 terabytes of storage using basic electrical and cooling estimation methods. Using methods documented in an APC whitepaper the cost savings varied from $24K/yr to $72K/yr for the same range. The electrical cost utilized was 9.67 cents per kilowatt hour (average commercial rate across the USA for the last 12 months) and cooling costs were calculated at twice the electrical costs based on data from standard HVAC cost sources. It was also assumed that the disks were in their own enclosures separate from the servers while the SSD could be placed into the same racks as the servers. For rack space calculations it was assumed 34U of a 42U rack was available for the SSD and its required support equipment leaving 8U for the servers/blades.

Even figuring in the initial cost difference, the SSD technology paid for itself before the first year was over in all IOPS and terabyte ranges calculated. In fact, based on values utilized at the storage performance council website and the tpc.org website for a typically configure SAN from the manufacturer used in the study, even the cost for the SSD was less for most configurations in the 25K-100K IOPS range.

Obviously, from a green technology standpoint SSD technology (specifically the RamSan 500) provides directly measurable benefits. When the benefits from direct electrical, space and cooling cost savings are combined with the greater performance benefits the decision to purchase SSD technology should be a no brainer.