8 Replies Latest reply: Apr 27, 2012 5:48 AM by Ilmar.Kerm RSS

    ASmLIB version

    915922
      Hi experts

      I have instale OEL

      uname -r --->>> 2.6.32-200.13.1el6uek

      what is the ASMLIB version compatbible with this

      thanx
        • 1. Re: ASmLIB version
          CKPT
          912919 wrote:
          Hi experts

          I have instale OEL

          uname -r --->>> 2.6.32-200.13.1el6uek

          what is the ASMLIB version compatbible with this

          thanx
          Refer Cannot Find Exact Kernel Version Match For ASMLib (Workaround using oracleasm_debug_link tool) [ID 462618.1]
          • 2. Re: ASmLIB version
            Billy~Verreynne
            912919 wrote:

            I have instale OEL

            uname -r --->>> 2.6.32-200.13.1el6uek

            what is the ASMLIB version compatbible with this
            ASMLib is not needed for running ASM.

            And I would again question why ASMLib should be used when default multipath (which you have already installed with OEL) has the feature set needed for providing consistency in device naming and dealing with multiple I/O paths. ASM works very well directly on multipath devices.

            I would also question why multipath, which origins stem from building the largest clusters on this planet, dealing with PB storage, and is still being used every day in such clusters, should not be used for Oracle ASM in favour of ASMLib....
            • 3. Re: ASmLIB version
              onedbguru
              Billy...

              glad to see others that agree that ASMlib is not necessary. Still don't know what was it's original intent, but I found it quite useless.

              I will reiterate: You DON'T NEED ASMlib to use ASM. After building and configuring more than 75+ clusters, again, you DON"T need it!!!
              • 4. Re: ASmLIB version
                Billy~Verreynne
                After throwing ASMLib out some years ago (incompatibility with EMC Powerpath) and building all our clusters with Multipath (after throwing Powerpath out too), I thought we were the only ones that used a proper Open Source stack that does not taint the kernel.

                Good to hear that we're not alone on this. :-)

                We've used (still are using) Multipath for fibre channel devices, SRP devices, SCST devices... and even a mix of these. Clusters ranging from RHEL3 to RHEL5 over the years. No ASMLib. No proprietary vendor s/w.

                No adding another s/w layer to the driver stack, without a single sound and sensible reason as justification for that. (and I've asked "why AsmLib" a number of times on OTN and never got a meaningful response as to what makes it better than not using AsmLib)
                • 5. Re: ASmLIB version
                  Sebastian Solbach -Dba Community-Oracle
                  Hi Billy,

                  as to "why ASMLib":

                  As far as my knowledge goes, ASMLib provides only one real advantage over UDEV/Multipath and that has to do with open file handles.

                  If you don't use ASMLib then each and every process of a database doing I/O will have a file handle open for each ASM disk.
                  When using ASMLib only ASMLib has the file handles open.

                  So on big server with multiple ASM disks and multiple databases this resource constraint may become visible.

                  Regards
                  Sebastian
                  • 6. Re: ASmLIB version
                    Billy~Verreynne
                    Thanks Sebastian.

                    A device or file handle is AFAIK not "portable" across process boundaries. So one process cannot use and open a handle and pass that to another process - unless it does something like redirecting that handle as the stdin and stdout handles of the new process, allowing that new process to use stdin to read and stdout to write to that device...? (but then I last did this type of thing on SVR4 so likely my understanding of this is outdated)

                    Will be interested to know the technical details of just how ASMlib goes about sharing(?) direct I/O device handles to multiple processes.
                    • 7. Re: ASmLIB version
                      onedbguru
                      Because it is Linux only, it becomes a non-starter for sites that have standardized system builds. I have not experienced any problems with running out of file descriptors even on systems with hundreds of disks and thousands of data files nor have I had of the problems described in the "ASM Under the hood" book associated with NOT using ASMlib.
                      • 8. Re: ASmLIB version
                        Ilmar.Kerm
                        To answer the original question... ASMLIB is already included in UEK kernel so no need to find the kernel driver.