Question on partitioning a storage array - Storage

This is a discussion on Question on partitioning a storage array - Storage ; Hello, please don't bash me if I ask stupid things. I am only an "acting admin". The situation is as follows: a storage box (3TB) configured as RAID5. One volume, one LUN. An FC switch. Three servers. I would not ...

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Thread: Question on partitioning a storage array

  1. Question on partitioning a storage array

    Hello,

    please don't bash me if I ask stupid things. I am only an "acting admin".

    The situation is as follows: a storage box (3TB) configured as RAID5. One
    volume, one LUN. An FC switch. Three servers.

    I would not like to use (for now) a clustering FS.

    I am reluctant to configure / reconfigure the storage. I know too little
    of these things.

    Are the following schemas allowed:

    1) connect the switch using FC to each of the servers, and then create
    three partitions (e.g. with parted or fdisk). Then mount at each of the
    servers only its own partition. Will that work reliably? In theory,
    the switch gives block level access to the shared device; the servers
    should not access anything simultaniously, and hence no data
    inconsitency should occur.

    2) the same, but use a LVM -- create logical partitions, and let the three
    servers use each its own logical partition.


    Again, sorry if the question is trivial or just plain stupid.

    j.

  2. Re: Question on partitioning a storage array

    January Weiner wrote:
    > Hello,
    >
    > please don't bash me if I ask stupid things. I am only an "acting admin".
    >
    > The situation is as follows: a storage box (3TB) configured as RAID5. One
    > volume, one LUN. An FC switch. Three servers.
    >
    > I would not like to use (for now) a clustering FS.
    >
    > I am reluctant to configure / reconfigure the storage. I know too little
    > of these things.
    >
    > Are the following schemas allowed:
    >
    > 1) connect the switch using FC to each of the servers, and then create
    > three partitions (e.g. with parted or fdisk). Then mount at each of the
    > servers only its own partition. Will that work reliably? In theory,
    > the switch gives block level access to the shared device; the servers
    > should not access anything simultaniously, and hence no data
    > inconsitency should occur.
    >
    > 2) the same, but use a LVM -- create logical partitions, and let the three
    > servers use each its own logical partition.
    >
    >
    > Again, sorry if the question is trivial or just plain stupid.
    >
    > j.


    I'd suggest not doing this. Three hosts sharing one partition table sounds
    like disaster. Say you reinstall the first host with the partition
    table. what happens to the other machines?

    divide the 3TB as needed into three luns. zone the luns to the correct
    hosts. Then there's no way at all they can botch up data on another
    machine. Also, there's no reason to present data to a host that it doesn't
    need to access anyways.




  3. Re: Question on partitioning a storage array

    On Wed, 24 Sep 2008 14:57:26 +0000 (UTC), Cydrome Leader
    wrote:

    >January Weiner wrote:
    >> Hello,
    >>
    >> please don't bash me if I ask stupid things. I am only an "acting admin".
    >>
    >> The situation is as follows: a storage box (3TB) configured as RAID5. One
    >> volume, one LUN. An FC switch. Three servers.
    >>
    >> I would not like to use (for now) a clustering FS.
    >>
    >> I am reluctant to configure / reconfigure the storage. I know too little
    >> of these things.
    >>
    >> Are the following schemas allowed:
    >>
    >> 1) connect the switch using FC to each of the servers, and then create
    >> three partitions (e.g. with parted or fdisk). Then mount at each of the
    >> servers only its own partition. Will that work reliably? In theory,
    >> the switch gives block level access to the shared device; the servers
    >> should not access anything simultaniously, and hence no data
    >> inconsitency should occur.
    >>
    >> 2) the same, but use a LVM -- create logical partitions, and let the three
    >> servers use each its own logical partition.
    >>
    >>
    >> Again, sorry if the question is trivial or just plain stupid.
    >>
    >> j.

    >
    >I'd suggest not doing this. Three hosts sharing one partition table sounds
    >like disaster. Say you reinstall the first host with the partition
    >table. what happens to the other machines?
    >
    >divide the 3TB as needed into three luns. zone the luns to the correct
    >hosts. Then there's no way at all they can botch up data on another
    >machine. Also, there's no reason to present data to a host that it doesn't
    >need to access anyways.
    >
    >


    That's definitely the most sound way to do it. If you're not looking
    at a CFS then you really need different luns per host.

    ~F

  4. Re: Question on partitioning a storage array

    January Weiner pisze:
    > Hello,
    >
    > please don't bash me if I ask stupid things. I am only an "acting admin".
    >
    > The situation is as follows: a storage box (3TB) configured as RAID5. One
    > volume, one LUN. An FC switch. Three servers.
    >
    > I would not like to use (for now) a clustering FS.
    >

    [CUT... ]

    if this is not for cluster - divide destroy 1 LUN, create 3 separate LUN's.

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