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  1. #1
    Join Date
    Nov 2000

    I am in the processing of selecting the physical partition sizes in AIX 4.3.3, Unix for my volume group. What effect on Oracle 8.1.7 (8k blocks) will choosing 32mb or 64mb have, if any?

    Also does anyone know how to find the Unix Block Size? I am under the impression this should be set to the Oracle block size = 8k.

    Are there any other (should be obvious) unix considerations I need to set for Oracle?


  2. #2
    Join Date
    Nov 2000
    Originally posted by kburrows

    Also does anyone know how to find the Unix Block Size? I am under the impression this should be set to the Oracle block size = 8k.
    df -kg .
    Jeff Hunter
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  3. #3
    Join Date
    Nov 2000

    df -i, indicates my filesystems in 512k blocks
    df -k, indicates my filesystems in 1024k blocks.

    This can't be the block size can it, it looks like I can display the block size anyway I want.

    I am more looking for the i/o block size . I thought the block size was set in the fragment size during the jfs creation. But this is where I am confused because I can only go as high as 4k there.

    Where do you set the block size?

  4. #4
    Join Date
    Aug 2000
    1. some little words about the space allocation in VG/LV

    When you create a Volume Group (VG), you specify the Physical Extent Size (PE). This depends upon the size of the inode-table you want + the total size of the VG.

    You can make Logical Volumes in this VG with size multiple PE.

    I don't think this is the real AIX-block size, but it's a real 'limit' you have to be aware of when creating VG and LV. eg. when you PE-size = 4M it's not possible to have a LV that is 6M large. it will have be 4M or 8M

    2. AIX block size

    I think the REAL AIX block size is 512 bytes.
    If you do a df, AIX will report all sizes in 512bytes blocks.
    If you do a df -k, AIX will report all size in Kbytes.

    3. JFS cache

    With regards to fast in/output, don't forget that AIX uses a lot of JFS cache.
    If you want, you can tune this using vmtune ( /usr/samples/kernel ) with the -p and -P options. This can help you reducing the JFSCache thus resulting in more memory that can be used the db.


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