Difference between asm and san

Dear all Guru's,
I have a question what is difference between san and asm because san also provide mirroring like asm,why we shuld go for asm.
Regards,
Jam

926840 wrote:
but i want to know if i don't use asm or use asm storage layer for oracle dbf file?.what is the benefit of using asm storage because some of organization don't use asm storage.There are two basic types of storage for Oracle databases.
"Cooked" file system. This means the disk is formatted and managed via a specific file system driver. On Windows, that would be ntfs. On Linux, that typically would be something like ext3.
This file system is managed by the file system driver loaded into the kernel. It does directory and file management, service I/O calls to read and write files, provides caching, and so on.
ASM does not support cooked file system as it already has a driver that manages that formatted file system drive/partition.
Raw disks is the second storage type. This means it is unformatted - and as such, you cannot (via standard o/s commands) use the drive to create/update/delete/etc directories and files.
ASM supports managing such raw (non-cooked) devices. As these devices are directly used by the database, the database can better control and managed device access.
Simple example. The database writes 10 8KB database blocks to a cooked file system. It has no idea whether those 10 blocks were actually written to disk.. or whether the file system driver has cached that write and all 10 blocks still sit in memory. The database itself also has a cache. So there are now 2 memory caches.. a physical database I/O may actually be a logical file system I/O.. These factors make managing and determining performance complex.
A raw non-cooked device does not have such a secondary cooked file system cache. If the database does a physical write to disk, the data is actually written to disk. There is a single memory cache that is managed by the database. Less complexity and less ambiguity. And it can also mean better performance.
Manually managing raw device is however complex. And in the past, problematic as the database directly used the raw device without providing any type of management layer for raw devices. ASM addresses that issue - and addresses it very well.
Using SAN LUNs as cooked file systems for an Oracle database does not make much sense IMO. SAN LUNs should be used as raw devices for the database - and ASM used as management layer for these devices.

Similar Messages

  • I would like to know the difference between OEL and RHEL

    I would like to know the difference between OEL and RHEL, are they same?
    If I test any application on RHEL, will it work on OEL too.
    Thanks
    Edited by: user10685113 on 08-Aug-2012 05:35

    The name OEL as such is not used anymore, since the product was renamed from Oracle Enterprise Linux to Oracle Linux with the release of version 5.5 in September 2010.
    The main technical difference between Oracle Linux and RHEL is that Oracle Linux ships with an Oracle exclusive and optimized Oracle UEK kernel. It does however still install and provide the original and older RHEL kernel for fallback.
    As of Oracle Linux 5.6, the Oracle UEK kernel is the default kernel. The current latest version of Oracle Linux 6.3 uses the Oracle UEK2 kernel, which is based on the Linux 3 kernel (2.6.39).
    Oracle Linux is binary compatible with RHEL.
    Oracle Linux has several advantages over RHEL, in particular if you plan to use it to install Oracle products.
    • The same kernel UEK and UEK2 versions are available for Oracle Linux 5.x and 6.x
    You do not necessarily need to perform a complete and unsupported system upgrade to use a newer kernel version and drivers.
    • Oracle Pubilc YUM
    Oracle provides a public yum repository for installing software packages including the latest patches. RHEL does not and requires a paid subscription for online access.
    • Oracle specific drivers and software
    Oracle Linux provides additional software and kernel drivers, for Oracle clustering, Dtrace, BtrFS and ASM, which is not available for RHEL 6.
    Oracle Linux provides additional packages which trigger the automatic installation of system software prerequisites, including kernel parameters and oracle account setup to install Oracle Database:
    oracle-validated (Oracle Linux 5)
    oracle-rdbms-server-11gR2-preinstall (Oracle Linux 6)
    And last not least you have just one vendor and support requirement for Oracle products.
    Have you checked the Internet:
    http://www.oracle.com/us/technologies/linux/index.html
    https://linux.oracle.com
    To obtain Oracle Linux:
    https://edelivery.oracle.com/linux
    https://wikis.oracle.com/display/oraclelinux/Downloading+Oracle+Linux (alternative)
    Edited by: Dude on Aug 8, 2012 2:29 PM

  • Difference between Null and null?

    What is the difference between null and NULL?
    When is each used?
    Thanks,

    veryConfused wrote:
    There is a null in java, but no NULL. null means no value. However, when assigning value, the following is different:Although the empty String has no special role. Null means, the referential type is not assigned (doesn't refer) to a specific object. The empty String is just another object though, so seeing it or pointing it out as something special when it actually isn't at all (no more special than new Integer(0) or new Object[0]) just adds to the confusion.

  • Difference between GUI_UPLOAD and WS_UPLOAD

    Hi,
    Please make me clear about the difference between GUI_UPLOAD and WS_UPLOAD. In which cases we need to use these modules...??
    Thanks,
    Satish

    I would suggest to always use the GUI_UPLOAD.  I say this because this is the function module which is used in the GUI_UPLOAD method of the class CL_GUI_FRONTEND_SERVICES.   Really, you should probably use the class/method instead of the function module.
      data: filename type string.
      filename = p_file.
      call method cl_gui_frontend_services=>gui_upload
             exporting
                  filename                = filename
                  filetype                = 'ASC'
             changing
                  data_tab                = iflatf
             exceptions
                  file_open_error         = 1
                  file_read_error         = 2
                  no_batch                = 3
                  gui_refuse_filetransfer = 4
                  no_authority            = 6
                  unknown_error           = 7
                  bad_data_format         = 8
                  unknown_dp_error        = 12
                  access_denied           = 13
                  others                  = 17.
    Regards,
    Rich Heilman

  • Difference between char and varchar, also the difference between varchar2

    Hi,
    Can anyone explain me the difference between char and varchar, and also the difference between varchar and varchar2...

    Varchar2 is variable width character data type, so if you define column with width 20 and insert only one character to tis column only, one character will be stored in database. Char is not variable width so when you define column with width 20 and insert one character to this column it will be right padded with 19 spaces to desired length, so you will store 20 characters in the dattabase (follow the example 1). Varchar data type from Oracle 9i is automaticlly promoted to varchar2 (follow example 2)
    Example 1:
    SQL> create table tchar(text1 char(10), text2 varchar2(10))
    2 /
    Table created.
    SQL> insert into tchar values('krystian','krystian')
    2 /
    1 row created.
    SQL> select text1, length(text1), text2, length(text2)
    2 from tchar
    3 /
    TEXT1 LENGTH(TEXT1) TEXT2 LENGTH(TEXT2)
    krystian 10 krystian 8
    Example 2:
    create table tvarchar(text varchar(10))
    SQL> select table_name,column_name,data_type
    2 from user_tab_columns
    3 where table_name = 'TVARCHAR'
    4 /
    TABLE_NAME COLUMN_NAME DATA_TYPE
    TVARCHAR TEXT VARCHAR2
    Best Regards
    Krystian Zieja / mob

  • The difference between Lion and Mountain Lion

    Can some one explain to me the difference between Lion and Mtn Lion? I'm currently 10.6.8 Is it beneficiall for me to upgrade?

    Mountain Lion is an enhanced version of previous OS X and so that is Mavericks.
    About upgrading it all depends on what your needs are and if your hardware supports it.
    System requirements for OS X Lion
    System requirements for OS X Mountain Lion
    OS X Mavericks: System Requirements
    Please check also applications compatibility. From Lion onward, you cannot run PPC application.

  • The difference between N80 and N80IE ?

    What is the difference between M80 and N80ie?

    02-Jan-2007
    07:45 PM
    korngear wrote:
    The Nokia N80 Internet Edition is a new version of this handset with the same hardware as the normal N80. It is due for release in Q4 of 2006 and will be available in Patina Bronze or Pearl Black, and has the following additional software included.
    Yahoo Go! for Mobile
    Flickr
    Some Amazon Branded Software
    'Download!' App management
    Internet Telephone - SIP VOIP Frontend
    WLAN Wizard
    Gizmo VOIP - Gizmo Project VOIP Frontend.
    \\en.wikipedia.org//
    @Korngear
    Thanks.
    Could N80 be upgraded to N80IE?

  • The difference between SFP+ and X2

    Dear Expert,
    I need to know what is the difference between SFP+ and X2! and can I use SFP+ card and module instead of X2?
    Thanks,
    Mohammad Saeed

    Hi,
    They are both used for 10Gig interfaces.  The difference is the connector type.
    SFP+ is LC and X2 is SC.
    You can not put an SFP+ into an X2 slot or X2 optic into a SFP+.
    HTH

  • Difference between ok_code and sy-ucomm

    Hi,
    Can any one tell me the difference between ok_code and sy-ucomm

    Hi,
    Actually OK_CODE and SY-Ucomm are the same. But experts suggest use of OK code for following reason:
    In each PAI event that a user triggers by choosing either a pushbutton on the screen or an element in a GUI status, the corresponding function code is placed into the system field SYST-UCOMM or SY-UCOMM and placed in the OK_CODE field (as long as the function code is not empty). Empty function codes are placed in neither the SY-UCOMM field nor the OK_CODE field.
    In your ABAP programs, you should work with the OK_CODE field instead of SY-UCOMM. There are two reasons for this: Firstly, the ABAP program has full control over fields declared within it, and secondly, you should never change the value of an ABAP system field. However, you should also always initialize the OK_CODE field in an ABAP program for the following reason:
    In the same way that the OK_CODE field in the ABAP program and the system field SY-UCOMM receive the contents of the corresponding screen fields in the PAI event, their contents are also assigned to the OK_CODE screen field and system field SYST-UCOMM in the PBO event. Therefore, you must clear the OK_CODE field in the ABAP program to ensure that the function code of a screen is not already filled in the PBO event with an unwanted value. This is particularly important when the next PAI event can be triggered with an empty function code (for example, using ENTER). Empty function codes do not affect SY-UCOMM or the OK_CODE field, and consequently, the old field contents are transported.

  • What is difference between abstraction and encapsulation ?

    Hi,
    I am trying to figure out the difference between abstraction and encapsulation but confused.
    Both are used for data hiding then what is the exact difference ?
    Thanks.

    Tushar-Patel wrote:
    I am trying to figure out the difference between abstraction and encapsulation but confused.
    Both are used for data hiding then what is the exact difference ?This is the picture I have:
    When you encapsulate something you get an inside and an outside. The outside is the abstraction. It describes how the encapsulated entity behaves viewed from the outside. This is also called the type. Hidden inside is the implementation. It holds detail information about how the type's behaviour is accomplished.
    It's a very simplified picture but I think it's quite accurate and it works for me.

  • What is difference between Iterator and Collection Wrapper?

    Hi all,
                  I dont understand the actual difference between Iterator and Collection Wrapper. I observed both are used for the same purpose. Could any one please let me know when to use Collection Wrapper and when to use Iterator??
    Thanks,
    Chinnu.

    L_Kiryl is right.
    Collections support global iteration (through collection->get_next( )) and local iteration (through iterator->get_next( )).
    Each collection has a focus object. Initially, the first object has the focus.
    Any global iteration moves the focus, which is published by the event FOCUS_CHANGED of the collection.
    If you want to iterate on the collection without moving the focus (and without triggering timeconsuming follow-up processes) you can use local iteration. To do so, request an iterator object from the collection and use this to iterate.
    And one more advantage of using iterator: it takes care of deleted entities. If you use global iteration then when you reach deleted entity it will be an exception. But there is no exception with iterator in the same situation.

  • What is difference between modify and update i am using

    hi
    what is difference between mofify and update
    my requiremen is to have three condition checkec while mofifying or updating from a internal table
    the three fields are
    cus no
    status
    date these all are primary key in the database table
    so which sould i use modify or update
    there might be entry already existing in database table or new entry to be created if already existin it should check on the primary keys and updatat if not it should add a record
    pls suggest whihc to use and how to implement the check on teh threee primary key
    like if modify ztable from table it_test
    now where condition ? can be used or not with modify? and if yes how
    if not should i use update will update create a new entry if no entry is there and please give syntex
    regards
    Arora

    Hi Nishant Arora,
    Modify: It works in performing two actions.
    They are: Insert + Update.
    For Example If a record that is exited in database, so you are modifying that record, it updates that particular record.
    Similarly, If the is not existed in the database, you are modifying it, it inserts a new record.
    Update: Update means just it updates the status, I mean it only updates the record. It doesn't inserts any new record if that particular record is not present in the database.
    These are the cases you need to write these statements.
    Syntaxes: :
    Go through this links please.,
    http://help.sap.com/saphelp_nw04/helpdata/en/e7/968aa8b2384dd9835f91e7f8470064/content.htm
    http://help.sap.com/saphelp_nw70/helpdata/en/fc/eb35eb358411d1829f0000e829fbfe/content.htm
    Reward points if useful
    Cheers,
    Swamy Kunche
    Edited by: Swamy Kunche on Jun 11, 2008 2:41 PM

  • What is Difference between SXMB_MONI and SXMB_MONITOR?

    what is Difference between SXMB_MONI and SXMB_MONITOR?
    Can any explain to this question.please?

    Hello,
    Both are same.
    SXMB_MONI is area menu which will contain all multiple transactions pertaining to monitoring.
    SXMB_MONI contains some functions viz monitoring for Bridging, Archived Msgs, Job overview, persistence layer analysis.
    SXI_monitor directly leads to the message monitoring for the IS, which is part of the SXMB_MONI.
    SXI_MONITOR directly executes the monitoring report.
    Thanks,
    Satya

  • Can Oracle be forced to use the spatial index for sdo_filter in combination with an or clause? Difference between Enterprise and SE?

    We’re seeing the following issue: sql - Can Oracle be forced to use the spatial index for sdo_filter in combination with an or clause? - Stack Overflow (posted by a colleague of mine) and are curious to know if this behaviour is due to a difference between standard and enterprise, or could we doing something else wrong in our DB config.?
    We have also reproduced the issue on the following stacks:
    Oracle SE One 11.2.0.3 (with Spatial enabled)
    Redhat Linux 2.6.32-358.6.2.el6.x86_64 #1 SMP Thu May 16 20:59:36 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
    11.2.0.3.0 Standard Edition and 11.2.0.4.0 Standard Edition (both with Spatial enabled)
    Microsoft Windows Server 2003R2 Standard x64 Edition
    However, the SQL works fine if we try it on Oracle 11.2.0.3.0 *Enterprise* Edition.
    Any help or advice would be much appreciated.
    Kindest Regards,
    Kevin

    In my experience sdo_filter ALWAYS uses the spatial index, so that's not the problem. Since you did not provide the explain plans, we can't say for sure but I think yhu is right: Standard Edition can't use the bitmap operations, and thus it'll take longer to combine the results of the two queries (because the optimizer will surely split this OR up in two parts, then combine them).
    BTW: when asking questions about queries here, it would be nice if you posted the queries here as well, so that we do not have to check another website in order to see what you are doing. Plus it will probably get you more answers, because not everyone can be bothered to click on that link. It would also have been nice if you had posted your own answer on the other post here as well, because my recommendation would have been to use union all - but since you already found that out for yourself my recommendation would have been a little late.

  • What is the difference between #variable_name and :variable_name?

    Hi!
    What is the difference between #variable_name and :variable_name?
    I have found that if we use alphanumeric variable then :variable_name return value in quotes but #variable_name without quotes.
    Why it does not work in the same way for variable default values when variable is used in filter? (It works in mapping)
    I use variable in filter like T.OUT_DATE>convert(datetime,:LAST_UPDATE_DATE,121)
    When I use my variable in package and do refresh it works fine. But when I try to execute the same interface with variable default value I get error. Seems that variable name has been not changed to the value. It does not work with default value in quotes neither without quotes.
    Any ideas how to solve that?
    Thank you in advance!
    Edited by: user13278245 on Sep 15, 2010 4:34 AM

    Question is how to make it work with default value, when I execute interface standalone, not in package? And why it works in mapping but not in filter?
    + I have found that it works if source is Oracle. It doesn't work only for MS SQL source.
    Edited by: user13278245 on Sep 15, 2010 6:43 AM

Maybe you are looking for