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  1. #1
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    May 2008
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    Logical Volume Manager?

    does anyone know if this is safe, i mean when i ordered the server they advertised 500 gb sataII but i never knew that they actually come with 2 hdd and somehow combined into one hdd like raid0
    i got one 320gb hdd and second 160 gb which together it count as 500? sounds like a joke to me but anyway They installed this Logical Volume Manager and wondering if its safe or if its same as raid0?

    / ext3 /dev/mapper/VolGroup00-LogVol00

  2. #2
    It should be fine. It is similar to raid0 but software based. You can set it up like Raid0.

    If that is the case, it does not seem like very ethical advertising.

  3. #3
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    May 2008
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    but what im afraid of raid0 is that if something happends it may corruppt all files on the hard disks. It happend before when i had raid0 software based.

    Yes, indeed Im not pleased how they advertised.

  4. #4
    Join Date
    Nov 2003
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    35
    Does the command pvdisplay show it as two drives?

  5. #5
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    May 2008
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    how do i check that? i use centos 5.1

  6. #6
    Join Date
    Nov 2003
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    35
    You type pvdisplay and hit enter on the command line.

  7. #7
    Join Date
    May 2008
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    --- Physical volume ---
    PV Name /dev/sda2
    VG Name VolGroup00
    PV Size 297.99 GB / not usable 20.87 MB
    Allocatable yes (but full)
    PE Size (KByte) 32768
    Total PE 9535
    Free PE 0
    Allocated PE 9535
    PV UUID szW4z3-Cp7d-eTAT-h3gp-Nkb2-2bkF-clQ5pR

    --- Physical volume ---
    PV Name /dev/sdb1
    VG Name VolGroup00
    PV Size 149.05 GB / not usable 17.31 MB
    Allocatable yes (but full)
    PE Size (KByte) 32768
    Total PE 4769
    Free PE 0
    Allocated PE 4769
    PV UUID yxjLSr-d5Up-h2Vu-WfiR-Oozn-RFbo-CHlZwh

  8. #8
    Join Date
    Nov 2003
    Posts
    35
    Personally I'd complain- if one of those drives blows out you might lose the entire volume group.. (maybe someone could comment that has experience with PVs failing on a VG?)

    Or at least create two separate volume groups, or if you don't need LVM just use regular partitions.

  9. #9
    Join Date
    Nov 2005
    Location
    Montreal, Qc
    Posts
    55
    I would ask for a repartitioning of the drives, as if one of the drive dies, the content on the 2nd drive can be corrupted as well (and probably will).

  10. #10
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    May 2008
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    ok, but isnt it same if i get one 500 gb hard disk?
    Last edited by Maikon; 06-11-2008 at 10:11 AM.

  11. #11
    Join Date
    Nov 2005
    Location
    Montreal, Qc
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    55
    In a way yes, since if you have 1 x 500 GB hard drive, and it fails you lose all data.

    But in another way not really, since statistically if you have 2 hard drives, and if either one fails you lose all data, you have 2x more chance that it happens then with 1 drive (as with RAID0, which should be used in a server setup very rarely, and in very specific conditions). Also the 160 gb drive is probably older, which can arguably increase the risk of failure.

    If you don't really need 500 gb of storage, using the 320 gb drive as primary, and the 160 gb as backup makes the best sense in my opinion, which can be done relatively easily by simply removing the 160 from the LVM group, and use it seperately (make sure you kow what your doing as doing this incorrectly can cause data loss).

    Also any way does not replace having a reliable off-server backup solution.

    Hope that helps. Cyb
    Last edited by Cyborg--; 06-11-2008 at 10:18 AM. Reason: Paragraphs

  12. #12
    Join Date
    Jul 2006
    Location
    Detroit, MI
    Posts
    1,962
    LVM is VERY robust. The ethics of the marketing are questionable, but if anything it will be a bit faster because you have 2 spindles.



    Regards,

  13. #13
    This isn't set up as raid0, if it were set up that way you would need both drives to have the exact same capacity or it would only use the first 160GB of your 320GB drive. I'm not sure how they set it up using linux since I'm not familiar with that enviroment but I would drop this scheme entirely and just use the drives as basic disks.

  14. #14
    Join Date
    May 2008
    Location
    FL
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    That is spanning. The data isn't broken up (and therefor offers no speed increase, unless you access data from different drives at the same time) but if either drive dies then the partition will likely be unrecoverable (if it spans both drives).

  15. #15
    Join Date
    May 2008
    Posts
    667
    heres what i got my reply from the staff, i do plan on getting a real 500 gb hard disk so they have to reinstall everything. Is this a better solution to pick?


    We apologize for such mistake made by our setup dept.

    Regarding LVM, since you did not specify what kinds of partitions you wanted, we normally just set it automatic when we install centos, and that use LVM.

    And with that, we can't just copy everything over to a new HDD and expect it to boot up, we'll need to reinstall centos on a new HDD then reinstall cpanel then move all backup data to the new HDD then restore each accounts via WHM.

    So before we proceed, please make sure you make the latest backup of all accounts via WHM and let us know where you put them. And let us know the kinds of partitions you want. Maybe we can use your new 500GB HDD to keep your backup?

    Or maybe we can add another 60GB HDD that you can use as backup drive? And avoid this reinstall

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