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Are There Large RDBMS Using Linux?
Jason Perlow of Linux Magazine writes:"
With all of the recent computer press coverage of Amazon and Intel converting their
web servers and other front end application servers to Linux, many of these stories
neglect to mention that the back end systems these companies use still rely on
commercial Unixes like Solaris, AIX and HPUX to host their RDBMSes (Oracle, DB2,
Sybase, Informix) for their mission critical transactional applications and data
mining.
Are there any companies out there actively using Linux to host a mission-critical
RDBMS ? or looking to replace UNIX with Linux for this purpose?"
Ok, maybe they are not huge, but Prada (Italian fashion designer and sponsor of "Luna Rossa" at the last America's Cup), uses Oracle running on RedHat stored on a pair of EMC Clariions for their datawarehouse.
I don't know what size the database is, but the Clariions had 400GB each worth of disks.
--
The world is divided in two categories:
those with a loaded gun and those who dig. You dig.
As distributions like SuSE continue pushing ahead with high-end features (like logical volume managers, which SuSE already has), usage of these products on Linux will undoubtedly increase. Part of the situation here is cost. When Oracle Enterprise Edition costs $40,000 per CPU, plus another $8,000 or so per year for support, who cares about spending a little more for high end Sun or IBM systems?
Also, Oracle 8i, while supported on Linux, did not offer a couple of features found in Oracle 8i for other systems. In particular, full interMedia support for full-text searches of all sorts of documents (especially from software made in Redmond) was not available in the 8i Linux version. The new 9i does support this feature under Linux.
If you are running a very large Unix box, such as an E10000, the operating system is optimized for the hardware, and the release of Oracle you're running is optimized for the OS. Even so, they still don't work that well--there are many unexplained bugs and glitches, even with the latest stable releases of Solaris and Oracle. No one would want to introduce further instability with a new OS.
Furthermore, there are no potential cost savings. Solaris essentially 'comes with' an E1000, and all your administrators are trained in Solaris.
When Oracle first started producing their appliance products, they were based on Sun's microkernel.
That has since changed. They are now using Suse Linux for all of their appliances. They work fairly well for what they are designed to do, which is to provide an administratively simple appliance... you don't deal with the OS, ony the Oracle admin interfaces.
Looking at my client list, 4 out of 12 of them are running various Oracle instances in Production on Linux, both Suse (the only officially Oracle supported Linux distro, if I'm not mistaken) and Red Hat. 9 of those 12 run Linux in development environments.
While the Linux deployment has usually been in a development environment, I've seen the trend start to move into Production environments. I think this can be attributed to a number of factors; the maturity/stability of Linux, the cost (hardware and software), the feature set (journalling file systems without having to pay through the nose for Veritas), and the hardware availability.
That and the fact that Oracle offers support for Suse. That is HUGE.
While the bigger companies are still using Solaris and HP-UX for their Oracle needs due to the hardware involved (I have yet to see an E10K run Linux, never mind in production), most of the smaller companies I deal with are running Oracle on Linux in some part of their company.
Also, a number of Oracle's newer integrated development tools (JDeveloper, Enterprise Manager, etc.) are being ported to be 100% Java so that they will (and do) run on Linux.
$0.02 (CDN)
Aside from this, much of the main databases (including almost all the mission critical stuff) here are on HP systems. Despite HP's uncertain future (having ditched PA-RISC), I doubt they'll move from HP in the near future.
Now take this reluctance to move between mainstream Unix vendors and apply this to linux, the upstart on the block. Quite aside from the "free" nature of linux and perceived lack of accountability, there's a further issue. Even when sticking with mainstream ventors, there's a reluctance to mix vendors; i.e. there's a desire to use IBM software on an AIX box, simply to avoid the finger pointing that can ensue. IBM have even had ad campaigns based on this. There's a certain comfort factor in knowing that you can go to one vendor and say "fix this" which you don't get with linux on Intel. IBM, HP and Sun all make the hardware and OS; you don't get that with linux (with the potential exception of some IBM kit like the S/390).
To get over this, there need to be vendors willing to support the software and hardware side of a linux solution. Hopefully IBM will pave the way with things like S/390 and the zSeries server.
Our company, a custom e-solutions provider, uses Oracle 9i on Linux almost exclusively because of Oracle's reliability and the fact that we have the resources in-house to support it. There is a caveat to this, though.
At $5,250 for just a 2-year. single processor standard edition license, 9i is not cheap and
most companies who already have an infrastructure built on it will not always realize a signifigant cost savings by moving to a Linux platform. 9i
Enterprise Edition is a cool $45K per processor so it is easy to see how the difference between $20K and $100K for an 8-way Intel versus an 8-way Sun
machine may not always be the determining factor in a platform decision for a system with a 5+ year time horizon.
i myself am in the datawarehouse of a large international company, our DWH is run off IBM as400's with DB2 + essbase/hyperion.
there are several factors why there will be no change in this.
IBM offers complete intergrated solutions (HW+SW) that you dont get with opensource solutions.
the opensource rdbms cant compete with the likes of DB2 and Oracle in terms of scalability and features.
3rd party integration. (Esssbase/Hyperion) database cube solutions dont exist for linux/freebsd. (man 3d cube db's are funky)
stable cross platform ODBC drivers, (winnt drivers for ASP, JODBC java+websphere, AS400 + RS6000 drivers)
support. (who gives 24/7 support on postgress, and send out tech support guys giving consultations, will come on site on a sunday at 4am?)
what OpenSource rdbms provide true mutli language support (we have records in cryllic, japanese, american, german, etc)?
high availablity (i dont know the current state of HA functionality in the linux kernel)
Linux on the AS400 is not seen as providing anywhere need the requirements at present, and its opensource database solutions are same.
(and i dont even think there is any cube database products in the opensource area... ???)
no sig for you
If you are running a VLDB on Oracle, you want a 64-bit system; otherwise the SGA is limited to 2GIG.
Oracle only supports Linux x86, with all of its 32-bit memory constraints. Does Linux implement memory windows like 32-bit HP-UX?
Also, at linux.sybase.com, you can download for free the Alpha-axp version of Sybase ASE 11.0.3.3 - this is probably the most available commercial 64-bit database for Linux.
Really, the Linux and WinNT versions of Oracle are at the low end of the food chain.
We have four linux machines using Oracle 9i RAC for our database. The boxes are penguin computing 200x Relions each with qlogic 2200 fibre channel cards and an Intel 10/100 dual nic card, which ties into our SAN'd up Clariion 4500 disk processor/array. The three nics (including the onboard) gives us a frontend/app network, backup network, and an oracle IPC interface.
We have had success using Redhat 7.1 (upgraded kernel to use LVM) and Suse 7.2 (comes w/LVM) for the linux distribution. Do not attempt RAC or OPS without an LVM of some sort. It can be done, but it shouldn't.
The biggest expense you will have is the disk array, and you should not skimp on this. Buy fast reliable maintained disk.
The Linux solution beats out Sun solutions in price hands down. You are talking $30,000 per box for the minimal Sun allowed hardware requirement for the Sun Cluster software with the Oracle Parallel DB runtime licenses (this has changed with v3 and so have the hw requirements). The Sun Cluster software requires an extensive review process by Sun which basically insures your company has two extra of everything and can be onsite to help Sun with their software and hardware in 4 hours. If your company doesn't have it's shit together, Sun and the few vendors that even know what Sun Cluster is aren't even going to bother talking to you about it.
This Linux solutions beats out a Windows NT solution in reliablity over the simple fact that the disk and volume management is clumsy. There is no easy way to create labeled raw devices on a Windows machine. The process as I remembered it was creating unlabeled logic partitions for each disk space and then maintaining a file pointing to the value of the related registry key to map out the tablespaces. As soon as you added a partition, modified a partition, or even used another node to look at the partition table, you and the database were screwed (i.e. restore). This problem with managing shared disk may have been fixed in 2000.
The weakest point in the entire Oracle 9i RAC is the cluster software layer. Whether you are using Sun's Cluster Software, the Oracle supplied cluster manager for Linux, or the hardware vendor supplied OSD layer for Windows. Be prepared to spend serious time in monitoring and getting it under control with appropriate patches.
Once you have fought your way through all of this you can reap in the rewards that multiple nodes with shared data gives you. The greatest benefit is the ability to partition your data and your application which allows you more opportunities to scale. If your data does not partition by some logical means (date, timezone, city, planet, etc) forget about it. Just get a big honking database machine (especially you SAP/Peoplesoft poor SOBs).
No.
I'm sure there are plenty large databases running on Linux and even MySQL. Solving the problem of large databases is relatively easy.
The much more difficult problems are availability (i.e. 7x24, runs for years with no interruption) and throughput.
When you combine these constraints to specify the problem of a large, highly available and highly active database that meets ACID test criteria, you have an enormously difficult problem. Until recently with the advent of Linux on mainframes Linux couldn't even dream of playing in this space simply because of the hardware it ran on. Sure, lots of people have Linux boxes that have uptimes for years, but some people have had to reboot because of a bad hard disk or other component. It doesn't happen very often, but it does happen. And the I/O bandwidth hasn't been there to support the kind of throughput needed at the high end.
Linux on mainframes doesn't really change this at all in the short term, even if you have a proven DBMS like Oracle (forget MySQL or Postgres), because the system as a whole hasn't proven itself. Question: How much money does an airline lose if it's reservation system is down for a few hours, even if it happens once every several years? How much money does a financial institution lose by being unable to execute transactions for even an hour? Answer: enough to buy plenty of proprietary software. People who run these kinds of applications are willing to pay the price for systems with a track record of success in this demanding area. They are often willing to sacrifice certain kinds of sophistication to ensure the safety of their company's critical operations.
I think that once Linux is established on the kind of iron that is needed for these applications, it will take as much as a decade before people will trust it for these kinds of missions. Phrases like "mission critical" are bandied about so they have little meaning; Linux is ready to support many applications that are important to businesses today, but can't be entrusted with other ones yet.
Nobody with a working application of the type I describe here is going to migrate to Linux. Nobody starting such an application from scratch will give more than a moment's consideration to Linux. The most likely entree into this space will be evolution of an application from something that is reasonable to host on Linux on small to midrange computers. If the company doesn't have the resources or the time to migrate to something more reasonable, the Linux will begin to get its shot at proving itself.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
A large database (in this context) is an enterprise-sized system: multiple platforms serving many millions of records in short periods of time.
I have customers fielding databases on multiple Enterprise 10000 servers...single tables of more than 35 million rows. This is actually a "medium" system in my mind.
I love Linux, I hacked around the pre 1.0 kernels many years ago. BUT, it does not scale up too well. Even the little things in Linux make it hard to do a good (maintainable) job: shifting device names (pull one of your HDs and see what happens), inability to modify hardware subsystems (storage in particular) while running live, etc. Even EMC, NetApp and XIOtech hardware can't fix these issues.
If the Linux crowd wants to be accepted by Big Business, they must learn the needs of Big Business.
Running a few 4-proc Intel servers with Oracle or Sybase does not put you in the same league. Nor does storing 10,000 articles in MySQL.
If you can imagine doing it yourself, if you can even imagine the amount of data to store, then you are almost surely below the threshholds I need to work in every day.