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Thread: RAID 5 degraded

  1. #1
    Join Date
    Dec 2010
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    4

    Default RAID 5 degraded

    Hello
    I set up a RAID 5 with four 640 GB Samsung drives under Ubuntu 10.4.
    After some days disk 2 fell out of the RAID. The RAID status now is degraded. All data is still available.

    Disk 2 is 'unused' state (disk information green). All other disks have a title like M0, M1 or M2 (disk information orange).

    What can I do to make the controller recognize the 'unused' Disk 2 again? Do I have to formate the disk before inserting? I would like to avoid to create a new RAID.

    Two more questions:
    - Is it possible to switch off the fans?
    - How can I configure sleep mode (spin down of disks) under Ubuntu?

    Thanks and regards
    Markus

  2. #2
    Join Date
    Dec 2010
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    4

    Default

    OK
    I bought a new disk, put it in (without formatting) and the RAID 5 was rebuilt successfully! Will have to check the old disk to find out why it does not work (anymore).

    Still have the two open questions:
    - Is it possible to switch off the fans?
    - How can I configure sleep mode (spin down of disks) under Ubuntu?

    Regards
    Markus

  3. #3
    Join Date
    May 2010
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    In the land of make believe.
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    501

    Default

    Try using DBAN to wipe the old drive, just do a one pass quick wipe. It should remove all partitions and pseudo raid data from the drive. Be careful with dban, connect the old drive as the sole drive in the computer when you wipe. dban is vicious and will annihilate all data on all drive by default.
    I AM NOT A PATRIOT MEMORY EMPLOYEE.

    But they have, on occasion, bribed me with hardware.



    I am happy to help, but don't PM me. Post a thread in the appropriate forum so others may benefit and offer assistance.
    Your lack of planning is not an emergency on my part.

  4. #4
    Join Date
    Dec 2010
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    4

    Question

    Quote Originally Posted by wittus View Post
    Still have the two open questions:
    - Is it possible to switch off the fans?
    - How can I configure sleep mode (spin down of disks) under Ubuntu?
    What happens if I give this command "sudo hdparm -B 128 -S 120 /dev/sdb" to my RAID?
    Could it be that the controller then spins the drive(s) down every few seconds? That was my impression.

  5. #5
    Join Date
    May 2010
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    In the land of make believe.
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    Default

    The fans do not have a handy switch, if you wanted to, you could probably unhook them, or modify them to run on a lower voltage (spinning slower). Of course, either of these would PROBABLY void your warranty.

    As for spin-down, the jmicron chip inside the convoy is actually pretending to be a SATA device. It does not pass commands on to the internal hard drives. As far as I know, there is no sleep mode in the spec for the controller chip. It does have a 'power slave/slumber' mode, but invoking that just puts the jmicron CPU itself to sleep. A notable oversight on jmicrons part if you ask me.

    If you are bored, and want a dry, technical, Chinglish explanation of the chips abilities, it is the JMB393, and the spec sheet can be found here.
    I AM NOT A PATRIOT MEMORY EMPLOYEE.

    But they have, on occasion, bribed me with hardware.



    I am happy to help, but don't PM me. Post a thread in the appropriate forum so others may benefit and offer assistance.
    Your lack of planning is not an emergency on my part.

  6. #6
    Join Date
    Dec 2010
    Posts
    4

    Thumbs up

    BadIntentions

    fans
    I 'unplugged' the fans from the controller board even before you sent your message.

    sleep mode
    I see. So there is no way to tell the controller to spin down the disks. Ok. I configuered the disks with hdparm outside of the RAID and put them back. But - to be honest - I don't know if this has an effect on the behaviour of the disks running within the RAID.

    spec
    Maybe I will have a look into the spec doc.

    I appreciate your hints and ideas. Many thanks!

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