Re: [suse-oracle] Oracle ASM driver for SLES 11

RE: [suse-oracle] Oracle ASM driver for SLES 11So , the only benefit I see is this:

    With ASMlib the disks are correctly released after having dropped a disk group (with block devices you must clean them (with dd))

(And I never ever did it - I released disks from the disk group and simple reused them in second group. And how often do you need to release a disks?)

And drowback is absolutely killer for the idea, except if vendor supports the library with the updates. Anyway, the risks of using ASMLib (risk is that it has a bug or new kernel was not tested with it) prevail any possible benefits.

Alex

PS. Any 3-d party modules in the kernel decrease system reliability (esp. after system updates). So, they can be used only if they provide really great benefits.




  ----- Original Message ----- 
  From: Yann Neuhaus 
  To: Alexei_Roudnev ; Arturo Gutierrez 
  Cc: [email protected] ; Arun Singh 
  Sent: Tuesday, March 23, 2010 3:21 AM
  Subject: RE: [suse-oracle] Oracle ASM driver for SLES 11


  Hi all,

  Advantages of Asmlib
  Limited number of RAW devices
  Kernel 2.4 :-) 256 RAW devices - Kernel 2.6 :-) 8192 RAW devices
  With AsmLib, no such limitation (or much higher)?
  However, note that since 10.2 RAW devices are not really necessary anymore on Linux, since ASM disk groups can be created directly on block devices (directly on /dev/dX)
  With ASMlib the disks are correctly released after having dropped a disk group (with block devices you must clean them (with dd))
  RAW devices are part of the kernel / distribution, AsmLib is an addon from Oracle, not part of the kernel

  Drawbacks :

  Modules are kernel-dependent. After every kernel-upgrade, a new version of asmlib module must be installed
  Without this module, it will be harder to access your data! (however it is still possible to "mount" the raw/block device in the Disk Group without ASMlib)
  Before every kernel update, you have to download a suitable asmlib module from Oracle Technet. Maybe it is not yet available!

  Best Regards

  Yann

  ----
  Yann Neuhaus
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  Infrastructure Managed Services CH-West

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  -----Original Message-----
  From: [email protected] on behalf of Alexei_Roudnev
  Sent: Mon 22/03/2010 20:49
  To: Arturo Gutierrez
  Cc: [email protected]; Arun Singh
  Subject: Re: [suse-oracle] Oracle ASM driver for  SLES 11

  Oracle supports ASM on normal disks since 10.2.0.4. So again, no one can
  explain me, why I need this piece of junk (ASMLib).

  What I do is simple
  - use aliases in 'multipath.conf'. SO disk1 always come as /dev/mapper/DISK1
  and so on.
  - so we create files as /dev/mapper/DISK0 etc
  - change disk search path to /dev.mapper/* and make sure (it may require 1
  change on older systesm) that ASM understand non-raw disks.
  - make sure that oracle own these files
  - use ASM over them.

  Why I need one more leyer to do exactly the same?

  Regarding CRS - yes, they suppoirt CRS on cluster file system (bad idea
  because OCFSv2 do nt share the master control with CRS / ASM) and on ASM,
  so realistically ASM is the only option for it. I just created 2 disk ASM
  group for OCRFile and 3 disk ASM group for CSSFile when tested it.

  PS> I am really tired of al this clueless changes in _what Oracle
  underastand and what do not_. Why could not they use normal block level
  disks for OCR and CSS (using ASM for cluster managemebt is, from any
  architecture point of view, a VERY BAD idea because you use higher layer to
  run lower layer - ASM is cluster file system, CRS is cluster manager, so it
  should not depend on any other clusterware).


  ----- Original Message -----
  From: "Arturo Gutierrez" <[email protected]>
  To: "Alexei_Roudnev" <[email protected]>
  Cc: "Arun Singh" <[email protected]>; <[email protected]>
  Sent: Saturday, March 20, 2010 3:03 AM
  Subject: Re: [suse-oracle] Oracle ASM driver for SLES 11


  Thanks for the reply s.

  Starting with 11g R2 , RAC installation offer only two options to store
  OCR and Voting disks.
  1. ASM Diskgroups
  2.Supported clusters file systems.

  Is not possible to specify raw or block devices directly in OUI screens.
  Oracle has deprecated raw devices support as some Unix vendors.


  Is true that ASMLIB is not mandatory and you can create ASM diskgroups
  using a variate of devices types, including multi-path , raw partitions etc.
  However, Oracle recommends install and configure ASMLIB. I think that
  lun persist ency across different s changes at the storage level can
  prevent bad functions in the drivers naming.

  Best regards
  Arturo

  Alexei_Roudnev escribió:
  > I really advise AGAINST ASMLib. IT is the piece of junk, technically
  > speaking, and Oracle works well on raw disks (10.2) or just normal disks
  > (11.1 and 11.2).
  > But if someone prefer ASMLib it should be here in SLES11.
  >
  >
  > ----- Original Message ----- From: "Arun Singh" <[email protected]>
  > To: "Arturo Gutierrez" <[email protected]>;
  > <[email protected]>
  > Sent: Saturday, March 06, 2010 10:37 AM
  > Subject: Re: [suse-oracle] Oracle ASM driver for SLES 11
  >
  >
  >>>>> On 3/6/2010 at 10:11 AM, Arturo Gutierrez
  >>> Hello,
  >>> I'm planning  a RAC instalation using Oracle RAC 11g R2 on SLE11
  >>> servers.
  >>> I'like install ASMLIB to manage disks. However I read from Oracle web
  >>> that the driver for SLES11 is built and distributed by Novell.
  >>> Do you from where source can I download this driver?
  >>
  >> ASMLib driver is part of SLES11 distro i.e. no need to download, just put
  >> SLES11 DVD & select asmlib driver in YaST
  >>
  >> For supporting libs & tools are available at:
  >> http://www.oracle.com/technology/software/tech/linux/asmlib/sles11.html
  >>
  >> Best,
  >> Arun
  >>
  >> _______________________________________________
  >> suse-oracle mailing list
  >> [email protected]
  >> http://listx.novell.com/mailman/listinfo/suse-oracle
  >>
  >


  --




            Arturo Gutiérrez Gómez


            Formador/Consultor  Tecnologias Oracle

  Oracle DBA Certified Professional OCP  [7.3-10g]
  Oracle Real Application Clusters Certified profesional


            Movíl 61 64 70 190




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