How to backup using RAID 1 without software - Does this work?

Discussion in 'other software & services' started by mrT__IT_that_is, Jun 1, 2009.

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  1. mrT__IT_that_is

    mrT__IT_that_is Registered Member

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    I am kind of rehashing this... since there was never a post saying yes this worked. There was a post back in 2004 ( https://www.wilderssecurity.com/showthread.php?t=44589 )

    Looks like "The private messaging system is currently unavailable" or I would just message the original poster (Devinco )

    I am faced with a situation where this seems like the lesser of 2^2 evils... Its a long story, but this would be a quick, and temporary, fix but I wanted to know if this actually works as far as in a DR situation.

    quick summery of what I have to work with and what we need done:

    2 windows servers (Win server 2003... one at main site, one at DR site)

    I would have 3 Hard Drives used to store data (HDD1, HDD2, & HDD3)

    I need to use RAID 1 (mirroring) on these drives.

    HDD1 & HDD2 will stay in the array. HDD3 will be removed and sent off site for a period and another put in its place. (this is in case our main facility burns down or what have you... This data that we are dealing with is large and we will only be working with it in the state it is in for a couple months... and we currently do not have the bandwidth to push over the wire to our backup facility. )

    If I put HDD3 in a server (at backup site), that had been restored from a backup of the server at our main site then brought the server online... would the server read the data that was on HDD3. (flat data only... no OS/system files)

    I know everyone who reads this is thinking why the #$^* do you want to do it this way... but with the regulations and time restraints that we are dealing with this is the quickest and seemingly most efficient way to get what we have to do done... most efficient way, if it works that is...

    so Devinco or anyone else... does/will this work?
     
  2. Sully

    Sully Registered Member

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    This is not a hot swap I assume. In your case then I would play it out like this. One of the drives will be primary in a 2 disk raid array level 1 mirroring. What is written to it, will be reproduced to the secondary disk. You may then remove this secondary disk, and insert a NEW secondary disk. The data will be mirrored to the NEW secondary disk, of course providing there are no disk errors on the original primary or the NEW secondary.

    You may then transport the original secondary disk to other location. If at this location you wish to also mirror this, you could place it as the primary in a two disk raid array level 1 mirroring, and the OLD secondary drive that already exists will be propogated with the original secondary disk that was transported. Providing all is set correctly.

    Then, after a time, you validate the server where the data originates from on both disks, remove the secondary disks, and SWAP them again. Data is held in original state on primary disk primary server, and also held on secondary disk secondary server.

    A hot swap drive would be even better, but those are not really cheap, depending. You could also invest in an eSATA raid 1 drive(s), and mirror over to this from the primary server, then have this mirrored unit travel to other place, and remain as a standalone mirrored apparatus.

    Many options without going over the wire.

    Sul.
     
  3. mrT__IT_that_is

    mrT__IT_that_is Registered Member

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    Thanks for the reply!

    I am using hot swap drives in an eSATA controller. I know the theory behind this should work... but I have never actually tried it.

    Since these are hot swap drives could I just rip out the 3rd drive while the system is running (but no I/O on the drive) and be done with it?

    I have used RAID for redundancy purposes (as does anyone who uses RAID)... and never needed to use the drive that I removed from an array... Should I power down the system first... for good measure? or should I not worry about it.
    Just wanted to be sure that it would be readable, I don't have a lot of time to test in depth... only with a little bit of test data and then need to use in production.

    Thanks again!
     
  4. Sully

    Sully Registered Member

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    I have 2 dell servers and one older micron with hotswaps. My dells have 5 scsi discs, and a 6th as a hotswap spare. So in my case if one of my drives go TU, I remove it and put the spare in place. The array is built again over the next few hours. In your case, with 3 drives, redundant mirroring level need to be known. Some levels say you need 2/3 drives to maintain integrity, some will be mirrored entirely on each drive. This means simple mirroring you could remove 2 drives and data still is entirely on lone drive. Other method, if you remove 2 drives, data is not all together. I forget what level that is, I think 5 but not sure as memory fails with lack of use lol. But on my hotswaps, I can pull one drive whenever I want, but not all data is there. On my older micron it is simple mirroring, so 4 drives all have exact duplicate. It is for family documents and important papers, so even though space is wasted across 4 drives, I don't mind as it is minimal use anyway. In that servers situation I could pull 2 drives and the data would be on both the 2 pulled and the 2 remaining.

    I would find out how the mirroring is working and what exactly the hotswapping capabilities are first.

    Sul.
     
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