I/O Bottleneck for Concatenated LUNs - Veritas Volume Manager

This is a discussion on I/O Bottleneck for Concatenated LUNs - Veritas Volume Manager ; I have a SUN Storedge A1000 connected to Enterprise 4500. The 12 disks in A1000 are grouped into 2 Raid5 LUNs (6 disks & 5 disks each) with one global hotspare. This is done using Raid Manager. Thus the OS ...

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Thread: I/O Bottleneck for Concatenated LUNs

  1. I/O Bottleneck for Concatenated LUNs


    I have a SUN Storedge A1000 connected to Enterprise 4500. The 12 disks in
    A1000 are grouped into 2 Raid5 LUNs (6 disks & 5 disks each) with one global
    hotspare. This is done using Raid Manager. Thus the OS sees 2 LUNs only.
    These 2 LUNs are concatenated in Volume Manager to form a single volume.
    IOSTAT shows bottleneck for one of the LUNs.

    Q1: If the 2 LUNs are c1t5d0 & c1t5d1, will one of them be completely used
    up before VM use the other? If so, how to know which one will be used first?

    Q2: How to know whether a file (of considerable size) resides in c1t5d0 or
    c1t5d1? Or does portions of the file reside in both LUNs?



  2. Re: I/O Bottleneck for Concatenated LUNs


    Sam,

    If you use vxprint command you can find out sd1 and sd2 . sd1 will fill first.
    Secondly there is no way to tell what files are allocated on what extends.
    you can tell about the filesystem that has been created on which disk by
    the size of the filesystem

    Simer


    "Sam" wrote:
    >
    >I have a SUN Storedge A1000 connected to Enterprise 4500. The 12 disks

    in
    >A1000 are grouped into 2 Raid5 LUNs (6 disks & 5 disks each) with one global
    >hotspare. This is done using Raid Manager. Thus the OS sees 2 LUNs only.
    >These 2 LUNs are concatenated in Volume Manager to form a single volume.
    >IOSTAT shows bottleneck for one of the LUNs.
    >
    >Q1: If the 2 LUNs are c1t5d0 & c1t5d1, will one of them be completely used
    >up before VM use the other? If so, how to know which one will be used first?
    >
    >Q2: How to know whether a file (of considerable size) resides in c1t5d0

    or
    >c1t5d1? Or does portions of the file reside in both LUNs?
    >
    >



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