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  • 1.  GPFS question.

    Posted Fri June 08, 2007 04:52 AM

    Originally posted by: SystemAdmin


    Hi guys,
    I have some questions regarding the restriping of a GPFS file system (version 3.1.0.9). For the sake of simplicity the cluster is consisted from only 1 node and no customization to the FS, just default settings. The GPFS was created with 2 disks in it, I suspended the second disk, and moved some data to the GPFS FS. Look below:
    bash-3.00# mmdf test_gpfs
    disk disk size failure holds holds free KB free KB
    name in KB group metadata data in full blocks in fragments
    -------------
    --------
    --------------------
    Disks in storage pool: system
    nsd0 71687000 -1 yes yes 59282432 ( 83%) 9208 ( 0%)
    nsd2 71687000 -1 yes yes 71619072 (100%) 336 ( 0%)
    -------------------
    (pool total) 143374000 130901504 ( 91%) 9544 ( 0%)

    ============= ==================== ===================
    (total) 143374000 130901504 ( 91%) 9544 ( 0%)

    Inode Information
    Number of used inodes: 4041
    Number of free inodes: 136247
    Number of allocated inodes: 140288
    Maximum number of inodes: 140288
    After that i resumed the disk and tried mmrestripefs -b with the idea to rebalance the data blocks across the 2 disks so i will have even I/O to both disks and not just reads from the first disk.

    bash-3.00# mmrestripefs test_gpfs -b
    Scanning file system metadata, phase 1 ...
    Scan completed successfully.
    Scanning file system metadata, phase 2 ...
    Scan completed successfully.
    Scanning file system metadata, phase 3 ...
    Scan completed successfully.
    Scanning file system metadata, phase 4 ...
    Scan completed successfully.
    Scanning user file metadata ...
    100 % complete on Fri Jun 8 11:31:43 2007
    Scan completed successfully.

    bash-3.00# mmdf test_gpfs
    disk disk size failure holds holds free KB free KB
    name in KB group metadata data in full blocks in fragments
    -------------
    --------
    --------------------
    Disks in storage pool: system
    nsd0 71687000 -1 yes yes 59483648 ( 83%) 9440 ( 0%)
    nsd2 71687000 -1 yes yes 71371520 (100%) 360 ( 0%)
    -------------------
    (pool total) 143374000 130855168 ( 91%) 9800 ( 0%)

    ============= ==================== ===================
    (total) 143374000 130855168 ( 91%) 9800 ( 0%)

    Inode Information
    Number of used inodes: 4041
    Number of free inodes: 136247
    Number of allocated inodes: 140288
    Maximum number of inodes: 140288
    As you can notice the restripe didn't rebalance the FS at all, from the docs i read i thought -b will rebalance the blocks evenly to all disks in the FS? I have to note that the data in the FS is 2 big files and that's all (8G and 3G). Am i missing something? Thanks in advance.


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