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QUESTION about version 4.7 upgrade to use 3tb parity(I'm currently w/out parity)

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hello all this is my first post and first build.


couldn't be going smoother as of now.  I'm built, had quite a bit of data to transfer (approx. 20tb), i have completed the transfer.  as per some recommendations to quicken the transfer i left the parity unbuilt until i was done with my transfer.  I'm now ready to build my parity.  and now that I'm ready I'm thinking i would probably prefer to use a 3tb wd green as my parity. 


but heres where my concern is. for my build i used version 4.7.  so it looks like I'm going to have to upgrade to a beta to use my 3tb drive as my parity.  wondering if i can i upgrade without a parity? (cause in the instructions it states you must have a valid parity to upgrade) or any recommendations/advice on how to proceed in order to use this drive as my beta?  and if I'm able to do so without too much hassle any recommendations on which beta to use?


i have a one spare 2tb as well that can be used if i have no other alternative.  but in retrospect ill have this 3tb just laying around unused if its not added to the array.


any help/advice/instructions would be greatly appreciated.  thanks very much


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Welcome to the forums.


One thing I would mention;

Personally, i feel that transferring 20TB to unraid without parity does leave for the possibility of data corruption if your drives are not pristine.

one thing I would do, if you still have your source file is to try and make sure your data is perfect. perhaps some sort of deep hash or binary comparison program before you erase your old data.


I am not saying you did it "wrong". it is just my personal preference to make sure you data is safe at all times. building without parity can lead to unexpected data corruption that you wont know about until you read the data back.


To answer your question. there is more then one way to get to the point you are asking about.

The way I would do it myself (others might have a better way).


I would first build parity with that 2TB drive you have under the stable 4.7 build.


I would then test parity after it is built in 4.7. This is a new build and we want to make sure it all looks good and that we can create and test parity before we move on..


do a little bit of testing make sure it is stable if you like.


If it all looks good. go ahead and do the upgrade to the bata of your choice.


Test that it looks OK, spin up and spin down the drives and copy some data on and off.


I personally would run parity with "data correction off "one more time to make sure you can still test parity in the new kernel.



check you syslog for errors.


If everything looks good, I would stop the array and upgrade the parity disk.


run parity again... then test file copies again.. double check the syslog


Yes, i said said a lot of testing... some of it is not "necessary", but, 20TB of data would be something I would want to make sure is safe at all times.

taking shortcuts or rushing things can lead to disaster.



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If you are copying from a windows machine use Teracopy and turn on checking. This makes sure what was sent is read back 100%.


There are many ways to deal with your array.

I'm not sure I would recommend switching to the beta with your production and only copy of data.

I wouldn't and I didn't and I'm a seasoned member.


You can use the 2TB drive for parity now. Do all your checking. Then run an md5sum or use md5deep to create your md5sum files per disk.


I have a compile package of md5deep here.



At some point you can use the 3TB for data or parity in 4.7 by short stroking it.

I.E. set the HPA via HDPARM to be 2TB in size.


In fact you can do that now for parity and use it until you upgrade. only thing is when you upgrade, to 5.x, you will need to reset the HPA, thus loosing parity and requiring a full parity rebuild.


It's probably easier to use the 2TB and wait to use the 3TB and if the worst case scenario happens, set the HPA on 3TB to replace a failed drive.



Johnm's procedure is a solid one, however, even limetech says this is a beta. it's been through 14 betas and there's still at least  another to come out due to other kernel issues.


If you have other backup copies if your data, then you can test with 5.x beta and recover should you need to.



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really appreciate the replies.  i won't go and do anything too rashly and stick with version 4.7 for now build my parity and move forward accordingly.  much thanks for the feedback.


i plan on already doing my second build for my father.  in order to utilize the 3tb drives he has i may try and build his using a beta (but maybe not i guess ill decide with a little more thinking/reading). 


its going to be the same data on both servers (he was my mirror backup) i was thinking on building his array and transfering all the data from server to server.  when i built mine i wasn't as concerned with data loss or failures since technically i was protected.  it will be a little of a different story now.  i figure ill build my parity while I'm preclearing his drives.  any suggestions on how to proceed with his build, but more importantly any suggestions on how to go about this transfer? much thanks any suggestions/feedback is greatly appreciated. 

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