8 Replies Latest reply: Nov 14, 2012 11:39 AM by jgarry RSS

    Oracle + SSDs

    KeenOnOracle
      Hi Friends

      I'm running oracle 11.2.0.3.0 on windows environment.
      We need to change our server that has began too old to attend our needs

      We're planning to run a SSD raid 5 for improve performance. Even though raid 5 is not the best solution for HDDs, it would be faster enough to even perform better than 8 HDDs on raid 10.

      Do you guys already run Oracle over SSDs RAID ?
      What about the performance on writting?
      What about the lifecycle of SSDs that are quite less than HDDs? I've heard from the vender that its about 6 years....

      Can we share experiences on that?

      Tks a lot
        • 1. Re: Oracle + SSDs
          jgarry
          This seems informative: http://www.pythian.com/news/28797/de-confusing-ssd-for-oracle-databases/
          • 2. Re: Oracle + SSDs
            doginthesun
            We run an 11.2.0.3 OLTP system on an EMC SAN with FAST Cache storage tiers. The FAST Cache software automatically migrates hot and cold blocks to/from the SDD drives. So far it seems to work real well and requires little administration on our end to keep track of what should and shouldn't be on the SDD drives.
            • 3. Re: Oracle + SSDs
              KeenOnOracle
              I just read this link now.
              Its written a year ago. perhaps something has been improved.

              Our idea is to have a RAID hosting the entire DB, which, based on the article, isn't good because of redos...

              Thats why I would ask someone running this way on production
              • 4. Re: Oracle + SSDs
                Mark Malakanov (user11181920)
                What about the performance on writting?
                SDDs are different. They may differ drastically in terms of speeds in different use patterns.
                Interfaces of SSDs are different too. Most have SATA III. Some have PCIe (the fastest ones). How fast is RAID 5 it depends on a SATA controller, most often it is so called "software RAID". In case of PCIe interface, RAID is totally "software". It will use CPU to calculate checksums and other RAID 5 data.
                What about the lifecycle of SSDs that are quite less than HDDs? I've heard from the vender that its about 6 years.
                lifecycle of SSDs is not measured in time. It is measured in writes.
                SSDs have a limit on a number of rewrites per block. Which is usually 1M. Time depends in intensity of re(writing) in your case.
                It means, in general, the bigger SSD the longer it can last.
                • 5. Re: Oracle + SSDs
                  sb92075
                  KeenOnOracle wrote:
                  Hi Friends

                  I'm running oracle 11.2.0.3.0 on windows environment.
                  We need to change our server that has began too old to attend our needs

                  We're planning to run a SSD raid 5 for improve performance.
                  With RAID5 for EVERY data block written, the XOR block must be rewritten;
                  which is a measurable penalty for write intensive objects like REDO files.
                  • 6. Re: Oracle + SSDs
                    jgarry
                    In my opinion, it is still a bleeding-edge technology. For my purposes, I avoid bleeding edge. Your purposes may be different. But you see, asking who's using it in production doesn't get much actual response. You have some amount of control over how interesting are the times you live in. The danger lies in making decisions based on what the vendors are selling, rather than your database needs. I can't see that much changes over a year, certainly in not how Oracle writes redo (although it has changed for exadata, the question becomes how long until the ability to [url http://structureddata.org/2011/10/12/exadata-smart-flash-logging-explained/]parallel write and only care about the fastest device is allowed to the rest of the world). I think it is hard to predict whether the self-tuning aspects of Oracle will handle these oddly fast devices appropriately, and if there are issues there, there could be some lag time before enough people complain that Oracle deals with it. Of course, they may be way ahead of me there, they aren't going to be completely reactive with a new version coming out, perhaps the developers got to play with new toys.

                    The EMC device someone mentioned sounds pretty cool, although I still have bitter memories of HP Autoraid moving stuff around inappropriately.

                    Of course the space shuttle was cool too. Note that the US is now dependent on big dumb Russian rockets.
                    • 7. Re: Oracle + SSDs
                      Mark Malakanov (user11181920)
                      I think it is hard to predict whether the self-tuning aspects of Oracle will handle these oddly fast devices appropriately, and if there are issues there, there could be some lag time before enough people complain that Oracle deals with it. Of course, they may be way ahead of me there, they aren't going to be completely reactive with a new version coming out, perhaps the developers got to play with new toys.
                      Just for information. Oracle offers whole line of flash storage devices, from SSDs to Flash Array.

                      http://www.oracle.com/us/products/servers-storage/storage/flash-storage/overview/index.html?origref=http://www.oracle.com/us/products/servers-storage/storage/flash-storage/ssd/overview/index.html

                      they are not as fast as others (like OCZ Z-Drive R4), but
                      these devices are certified with Oracle Database 11g R2 Smart Flash Cache - kind of transparent extension of buffer cache to flash memory (SSD).
                      • 8. Re: Oracle + SSDs
                        jgarry
                        Yes, those things look cool too.

                        What bothers me is the general PHB mindset of "lets just buy SSD and nothing else because it will make our windows server go so much faster." Another way of saying "throw hardware at it = good."