RAID 5 and Oracle Databases

While researching the effect of RAID 5 disk configuration on Oracle databases I came accrost more than I thought I expected on the topic.

With disk as cheap as it is today there is no reason to ever use RAID 5 on an Oracle database. Even for a database which sees only a moderate amount of updates the performance loss incurred by using RAID 5 is too high. RAID 1 or some combination of RAID 1 and RAID 0 should be used when high availability is required. Database 10g users should also consider allowing Oracle’s new Automatic Storage Management to handle redundancy on un-mirrored disks (or even raw partitions.)

But don’t take my word for it. Here are some opinions from some notable Oracle administrators:

Oracle Database RAID 5
Mark Rittman

No RAID5. Use RAW whenever possible and consider RAID10 or 0+1. RAID 5 can severely affect performance on highly updated databases.

Oracle Database Administration: The Essential Reference
David Kreines & Brian Laskey

RAID-5 is, in fact, very powerful and inexpensive. It is also a technology to be avoided in most cases when configuring your Oracle database! This may seem a harsh statement, but the reality is that although RAID-5 provides good levels of data protection at a low monetary cost, this comes at a very high cost for disk I/O. In particular, write operations on RAID-5 arrays can be orders of magnitude slower than the same operations on a single disk.

Oracle and RAID usage
Mike Ault

Use RAID10 when possible, RAID5 if it is not. Size the array based on IO needs first, then storage capacity and you can’t go wrong.

Disk Management for Oracle
Donald Burleson

Oracle recommends using (SAME) Stripe And Mirror Everywhere (a.k.a., RAID 1+0) for all systems that experience significant updates. This is because of the update penalty with RAID 5 architectures.

Using RAID 5 for a high-update Oracle system can be disastrous to performance, yet many disk vendors continue to push RAID 5 as a viable solution for highly updated systems.

RAID 5 is not recommended for high-update Oracle systems. The performance penalty from the parity checking will clobber Oracle performance.

If you’re still not convinced check out This site is committed to the Battle Against Any Raid Five (or four or free, uh, three.) The site has links to several more articles exposing the perils of RAID 5.

oracle, rdbms, dba, systems administration, sysadmin, raid, raid 5

Synergy – Cross Platform Mouse and Keyboard Sharing

SynergyTim Haroutunian recently discovered the open-source, cross-platform utility Synergy which allows you to seamlessly share a keyboard and mouse with several computers of varying platforms.

The behavior of Synergy is similar to having multiple monitors on a single computer with the added advantage that you’re controlling multiple systems. Since I have both a Mac OSX desktop and a Windows laptop on my desk it was nice to reduce myself to one keyboard and mouse! Even clipboard data is shared between the systems.

Setup was a little less than intuitive but well worth it. Out of the box, security is fairly weak, however the Synergy project page does have instructions on how to tunnel Synergy traffic through SSH. Mac, Windows and Linux binaries are available along with the source code for those DIYers.

kvm, cross-platform, software, systems administration, linux, OSX

UNIX Find And Execute

Zach tells me I need to post how to find files and execute a command on those files. While the man pages are always the definitive reference, these are the options I use frequently. As usual, anything in italics should be replaced with the details for your search.

Note: WordPress loves to convert quotes into fancy quotes (pointing in from each side) so these commands may not work too well if copied and pasted. On the bright side, there’s no time like the present to start commiting these to muscle memory.

Find a file and execute a specific command:

find path conditions -exec command {} \;

find ./ -name "*.php" -exec cat {} \;

The open/close curly bracket marks where the name of each file found will be substituted and the backslash-semicolon marks the end of the command to execute.

Here are a few other options I use frequently:

Search for a file by name:

find path -name filename

find ./ -name style.css

Search by name with wildcards:

find path -name "filename"

find ./ -name "*.html"

Search for files modified within the past n days:

find path -mtime -n

find ./ -mtime -7

Search for files modified before the past n days:

find path -mtime +n

find /tmp -mtime +3

These are mostly based on my experience in Solaris using the bash shell. They should work just about everywhere, but check the man pages as mileage will vary.

Easy Linux CommandsFor more tips like this check out my book Easy Linux Commands, only $19.95 from Rampant TechPress.

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unix, solaris, linux, mac osx, osx, sysadmin, systems administration

Sun Fire T2000 vs. Sun Fire V440

SunFireT2000Thanks to the diligence of my coworker Scott Maziarz we have been able to run some practical performance tests on the new Sun Fire T2000 we got on a try and buy program from Sun.

About our environment

While we’re not truly equipped for traditional load testing here at Plymouth State University I decided early on that our daily datamart scripts would be a good test of this system’s capabilities. These scripts are a combination of vendor supplied and homegrown code which create datamarts for reporting. The scripts run separately take between a minute and several hours to complete. They rely heavily on joins and functions so, while there is a fair amount of disk I/O, the speed of the processors and memory should play a large role.

Oracle 9iR2 was used for the testing on both systems. The database configuration was not altered, so despite the point that the T2000 has twice as much memory as our V440s (16GB versus 8GB) Oracle will be using the same amount of memory on both systems. We also unfortunately did not have the opportunity to do any performance tuning on the T2000. As such I consider this a comparison with a straight out of the box T2000. With some careful system tuning the T2000 would probably perform even better.

The two systems

Sun Fire T2000

  • 8 core 1.0GHz UltraSparc T1Processor
  • 16GB memory
  • 2 * 73GB 10K RPM SAS hard disk drives

Sun Fire V440

  • 4 * 1.0GHz UltraSparc IIIi
  • 8GB memory
  • 4 * 73GB 10K RPM Ultra320 SCSI hard disk drives

While these two systems are different in many ways they are comparable in price (the V440s are actually quite a bit more expensive, but this one is around two years old now.) All testing was done on internal disks making the results dependant on the entire system performance.

Oracle was not reconfigured to take advantage of the extra memory in the T2000.

The tests

For the testing we chose a set of 19 datamart creation scripts which we run daily in our production environment. To assure that there is no additional load on the V440 we ran the tests on our reporting instance which is on a relatively idle system.

The first test is to run the 19 datamart scripts staggered. This is how we run them in production. Four scripts are started every half hour to spread out the load on the server. There’s a lot of overlap, but the staggering is enough to keep the system responding normally.

Scripts running staggered

The graph above represents the runtime of each job individually. A shorter line represents a quicker runtime and we can see that the T2000 consistently outperformed the V440 often running n a quarter the time!

The total runtime for all 19 jobs was 2915 minutes on the V440 and 847 on the T2000. On average it took only 29% as long for the jobs to run on the T2000!

For the second test we ran all 19 jobs at once.

Scripts running simultaneous

We still see a significant improvement in performance, but not as high as when these were run staggered. Here the T2000 completed the tasks in 59% of the time of the V440. I attribute this to contention for disk on the T2000.

Thanks to Scott Maziarz for running the bulk of these tests and compiling the results for me.


The Sun Fire T2000 has certainly proven its worth. Some may be put off by the relatively low processor speed (the model tested was a mere 1GHz) but it is clearly not an impediment. The 8 core CPU seems to be up to the challenge and I’m sure with additional tuning I’m sure they’d scream.

With increased performance and higher efficiency than the comparably priced V440, the T2000 will definitely be in our future. The lower energy consumption and lower heat output would be a welcome change in our already taxed data center and the compact 2U size should be an easy fit in any rack.

Check out more details at Sun’s website and if you’re still not convinced apply for your own free 60-day trial!

sun, sun fire t2000, t2000, server, systems administration, database administration, dba, oracle, rdbms, sysadmin, sun microsystems

Getting Started with the Sun Fire T2000

SunFireT2000After receiving my try-and-buy Sun Fire T2000 over a week ago it’s finally up and running. While we have yet to hit it with much of a load, here are some thoughts on the out-of-box experience:

Before even powering up there are a couple interesting observations about the system. The first is the lack of power button, switch, or key. In fact there is only one button on the system and that is an indicator button which just flashes an LED on both the front and back of the system to make it easier to locate (a nice feature, by the way.) You’ll quickly find the hot-swappable dual power supply and fan compartment. The adventurous will find and the big button on top of the system which allows you to gain access to RAM and other non-hot-swappable components.

All of these compartments and components are accessible without the need for tools. The hard drives are on hot-swappable sleds which pop out the front of the box. The hard drives are small (2.5″ I believe) allowing room for 4 bays in the front and still affording enough space for ventilation. I was somewhat surprised to find laptop-style drives in a Sun server, but I guess I can’t come up with any reason not to.

After giving the hardware a good once-over it was time to get the T2000 up and running. I have to say Sun came up a little short on the out-of-box experience at this point. I’m comfortable with, even partial to the absence of on-board video on a server, and Sun has chosen to include serial via RJ-45 on the T2000. Sun was on the right track including two cables appropriately shielded for use with this port, but neglected to include an adapter to go to the 9 pin serial we all have on the back of our PCs.

After rummaging around for the proper adapter to hook the T2000 to an old laptop we plugged it in. The system is surprisingly (read obnoxiously) loud, but hey, it’s a server not a desktop. After a few minutes of the regular hardware diagnostics stuff the system came up to an sc> prompt.

This is where those who are not familiar with Sun’s newer hardware will come to a complete stop. The only documentation included with the system is the Sun Fire T2000 Server Getting Started Guide and that does little more than tell you what the different lights mean and where you can find more documentation online. If you get online and grab the Sun Fire T2000 Server Installation Guide this will walk you through dealing with the SC serial management port. In my opinion Sun should have included this one in hard copy with the system as well.

After a couple more steps things start to feel familiar and the rest of the setup is much like the Solaris 7, 8, and 9 installs I’m used to. With just a few extra steps here you can (and I’d recommend) configure the SC Network Management port which will allow you the same functionality as the SC Serial Management port without the need for the serial cable and adapter. You will need an extra network drop and IP address to use network management, but then you’ll be able to telnet to it for administrative functions. Of course in a production environment you’d want this behind a firewall or on a private subnet.

Other than that the system seems quick. Our next step is to get Oracle on the system and throw some queries at it. I’ll share more as soon as we get some results.

UPDATE: I have now had the chance to test drive some Oracle jobs on this system. Check out my findings here.

database, database administration, database administrator, dba, dbms, rdbms, solaris, sun, sunfire, sysadmin, system administration, systems administration, t2000, try and buy, unix, oracle