This is in response to a question I received in another blog post concerning the mapping of physical PCIe slots to the two controllers (and subsequentially CPUs). The answer (basically the table below) is big enough to justify it’s own blog post. Continue reading
I have previously written about my experience with wifi on a plane, today I am at the OUGN conference on a cruiseship between Oslo an Kiel which offers a satellite internet link. Simon Haslam just asked via twitter how the experience was since he was unfortunately not able to join this part of the trip but was curious. Obviously, the connection is good enough to use twitter and also do a bit of work on the internet, but due to the high latency of several seconds, it is not as interactive and usable as one might be used to. It also makes you appreciate websites that deliver as much information as possible with as little extra elements as possible. But there is no reason to complain, there are a bunch of fantastic Oracle Speakers on this boat and the view is awesome. Continue reading
While Oracle may – even with the newest release – not be web scale, it sure has flex everything in RAC. These are actually really great features but with the names being so similar (just like flash and flashback in current releases), it is easy to get them confused and I had a very hard time explaining these technologies to Martin Berger and Allan Robertson via twitter. The two features I want to write about today are flex ASM and flex cluster and I was lucky enough to sit in two excellent presentations by Markus Michalewicz and Nitin Vengurlekar at Collobarate 2013. Continue reading
I just received the fantastic news that OTN is recognizing me as an Oracle ACE Director. I feel very honored to be considered part of this special club.
The Oracle ACE program awards enthusiasts and community contributors by ackowledging the effort they put into sharing of knowledge. In addition to that the ACE Director designation supports individuals additionally to engage even more with Oracle through regular web conferences with engineering, an annual briefing before OOW and assistance with speaking opportunities. All they are asking for in return are things I enjoy doing anyway: Write the occasional blog post or article about Oracle technologies and speak to and with old and new friends and fellow nerds at conferences to share and spread enthusiasm for technology.
Thanks go out to everyone in this community for giving so much knowledge and motivation to share. You are great friends and I enjoy every meeting at conferences aswell as following you guys on the interwebs. My partners and colleagues at portrix, thank you for providing a platform where innovation and constant learning is encouraged and seen as competetive edge. My parents who are still driving me mad by demanding I come and fix their PCs (they have more than me) every time they accidentally delete “the internet”. According to them, “fixing PCs” is what I studied in college and what I do for a living. And I guess they are not too far off.
Larry Ellison himself just announced the latest generation of SPARC processors. Both he and John Fowler talked a lot about benchmarks and how these systems compete with IBM power series systems. Very exciting stuff but the announcement lacked a bit of technical details. I have compiled some information about these new systems:
The T4, T5 and the M5 share more than the names suggest. All of those CPUs are made up of the same basic building block: The S3 core. So each of those processors has the same basic per-core features of 8 threads, two pipelines and everything else that has already been present in the T4. The T4 has 8 of those S3 cores per chip and 4MB of L3 cache. The difference to the T5 is it packs twice the cores and memory: 16 cores and 8MB L3 cache and clocked at 3.6GHz compared to the T4′s 2.85GHz (3GHz in the T4-4).
The name M5 would suggest a successor to the chips used in the M3000 to M9000 series systems, the SPARC64. But in fact the M5 CPU is really made up of the same S3 core as the T4 and T5 with 6 cores and 48MB L2 cache. So all of these chips will support Oracle VM for SPARC (I still like to call it LDoms) even with live migration across these machines. They also all feature 10GbE and acceleration for cryptographics directly on the CPU.
The T4 systems are still available and won’t be EOL’d anytime soon. In fact, the T5 completes the portfolio on the top end while smaller and mid-size systems are still only being covered by T4 systems. The glueless 8 socket T5-8 systems is the top end of the line with 128cores that all access the same main memory with a single hop. But even when you compare the 2 and 4 socket variants it becomes clear that for T5, size does matter. What Larry and John did not mention was that in addition to the T5-2, T5-4 and T5-8 there will also be a T5-1B blade module with just a single T5 CPU but there will be no T5-1 (as of today).
I am obviously a big fan of Solaris but I am also very curious if Oracle will ever bring Linux to the SPARC platform. Back in the very old days, SUN hat a cooperation with ubuntu on the T1000 and T2000 systems for some time but it was not a huge success. Larry has made some comments in the direction of wanting to port OEL to SPARC in 2010 but still has to follow suit.
Oracle has yet to update the core factor table to include the factor for T5 chips. Anything but 0.5 would put a dent into all performance/price calculations. The core factor table has been updated and lists both the T5 and M5 processors with a factor of 0.5 which means that organizations can upgrade existing SPARC or Intel database systems to the same number of T5 cores without having to worry about adding extra costs for new DB licenses. Additionally, LDom virtualization and hard partitioning help out by allowing to run a database on a subset of cores and only license what you actually need or use.
I just received a long error stack followed by this nice little request to log an SR and report this.
pkg: This is an internal error in pkg(5) version 93c2e5a1fc89. Please log a Service Request about this issue including the information above and this message.
I guess we’ll see if the issue will be improved by my report but having logged a lot of feature requests and bug reports recently I have to say it is very satisfying to go over release notes and find fixes for things you reported. Btw if you are curious what happend up there: I (actually a script I was calling) tried to set up a repositpory from a local directory which had some whitespace in the path which is apparently not cool if you want to turn that into a URI.
The Oracle Desktop Virtualization team just released the latest versions of VDI and Sun Ray (Oracle blog: What’s New). This is following a rough schedule of (major) upgrades about twice per year and while a lot of the changes are maintenance and bug fixes there are some cool new features aswell. So let’s get started with the list of new things that I find interesting and/or useful and will definitely play with (and blog about) in the future:
And then there is a long list of bugfixes and minor improvements which a lot of look very familiar because they have been submitted by us. I especially like the fact that SRS auto-failover is now disabled by default. I had talked about this in my presentation at DOAG last November. The old default behavior was to fail-over the Sun Ray primary when the master crashed or was rebooted. This sounds like a good intention but in Sun Ray all secondary servers have to restart on such a change and this usually introduced more problems than it solved.
Another improvement is a new parameter (client.select.always) to control the display of available desktops even if all your desktops could be launched on all your monitors: In VDI 3.4 if you had two desktops assigned and a DTU with two monitors, VDI would automatically start both desktops and put them on your screens. This can be very useful for using two different operating systems with just one keyboard and mouse. But sometimes you only want to bring up a single desktop and use both monitors with it. The workaround was to create a third “dummy” desktop so that the number of screens and desktops did not match anymore to bring up the selection screen.
Next up: Secure Global Desktop (SGD) Version 5, please.
Heute Morgen sind die virtuellen Wahlurnen bei der DOAG geöffnet. Alle Mitglieder wählen die Vertreter der Delegiertenversammlung. Diese neue Gremium wurde durch eine Satzungsänderung im letzten November eingeführt und übernimmt den Großteil der Aufgaben der Mitgliederversammlung. In Zukunft entscheiden und entlasten die Delegierten über den DOAG Vorstand, und nehmen den Finanzbericht ab.
Als Vertreter für korporative Mitglieder mit weniger als 500 Angestellten stelle ich mich ebenfalls zur Wahl und freue mich über jede Stimme aus der Mitgliedschaft. Eine entsprechende email mit einem Link zum “Wahlzettel” wurde in den letzten Tagen verschickt.
Today, I attended an informal Oracle breakfast event which included a presentation by Joerg Moellenkamp about best practices for running Oracle databases on ZFS filesystems. There is a whitepaper that describes most of the issues that you should consider. In this post, I’d simply like to share my notes on the presentation, things that I find important or were new to me.
Joerg made a case for using ZFS to mirror data because this will give ZFS another chance to repair broken blocks or checksums. I never thought about it that way and preferred to let the SAN take care of mirroring but I will consider this in the future.
I was aware that the more a zpool got filled up the more effort it was for the system to find free blocks and that this leads to slower performance. What I did not know is that zfs actually switches to a different algorithm to find free blocks at a certain level and that this level is configurable with metaslab_df_free_pct. Older releases switch at about 80% full and try to find the “best fit” for new data which slows things down even more. Read more about it here.
One issue that I did find out just a few days ago is that you cannot set the primarycache and secondarycache parameters independently. The way that L2ARC caching (using read-optimized SSDs as cache devices in a hybrid storage pool) works is by only writing to this second level cache when data is cleaned out from the primary cache. So if you disable the caching of data or metadata for your primarycache (memory), then this data will also never make it’s way to your SSDs. This post is really helpful to understand the internals behind it (and then it becomes very obvious)
The theory of “IOPS inflation” was also briefly discussed: Due to ZFS’s copy-on-write behaviour, blocks that are updated get written to a different location on disk which may lead to a degradation in performance for sequential reads that would benefit from the blocks being in the ‘proper’ order like backups or full scans. While this has not been an issue for our databases (and Joerg also mentioned that he only knows one case), I’d like to take some time and construct a demo for some further studies sometime.
Update 2013/02/27: Bart Sjerps wrote an excellent blog article that shows the fragmentation on the physical disks that occurs when updating random blocks with Oracle on ZFS. He uses SLOB and introduces a searchable ASCII string to look at the raw files. There is no conclusion (yet) about how big the impact on performance for full scans or backups are but it does become very clear that fragmentation does easily occur and that this will lead to more IOPS to the disks to read a number of “sequential” blocks.
Wahrscheinlich ist die Ankündigung etwas kurzfristig, aber am 21. Februar wird es in Hamburg wieder ein Oracle Business Breakfast geben, bei dem Jörg Möllenkamp und Dirk Nitschke über Datenbanken auf ZFS und ZFS Storage Appliance sprechen werden während Teilnehmer auf Kosten von Oracle frühstücken. Das Konzept hat sich schon bei den letzten Veranstaltungen bewährt, und das Thema verspricht sehr interessant zu werden, zumal wir uns erst kürzlich damit beschäftigt hatten. Zur Anmeldung.
The release notes of Solaris 11.1 mention a new network trunking feature that does not require LACP or the setup of ICMP. I finally had time to look a little bit closer at it. The motivation to do trunking or aggregation are availability and load-balancing. The idea is to combine multiple interfaces so that the system survives the failure of a NIC, cable or switch (availability) and to also allow a higher throughput of data than what a single interface could provide (load-balancing). With Solaris 11.1 there are three basis methods to choose from and I want to briefly introduce them. There actually is a pretty good comparison chart in the documentation. Continue reading
Without much fanfare, an update to the Oracle Virtual Desktop Client for Oracle VDI or Sun Ray servers showed up on iTunes today. Version 1.2 promises improvements with the user interface, new gestures, higher screen resolutions, clipboard support to copy text between OVDC and the iPad aswell as dynamic session resizing to automatically change the resolution when you rotate the iPad from landscape to portrait mode. Continue reading