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Prceleared 3TB HD with a starting sector of 1. Can I change it?

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Hi everyone,

I precleared a 3TB HD and by mistake I let it define a starting sector of 1. Is there someway I could change the starting sector to 1 or do I have to preclear again?

 

I am certain I have seen a similar post but I cannot find it...

 

Thanks in advance for your help.

I know you can do this, just not sure if it works with 3TB drives (I know it works for < 2.2TB drives):-

-C 63    = convert an existing pre-cleared disk to use sector 63 as a
                  starting sector.
-C 64    = convert an existing pre-cleared disk to use sector 64 as a
                  starting sector.

 

Direct copy and paste off the preclear help page (E.G. when you run the script with no parameters).

Hi everyone,

I precleared a 3TB HD and by mistake I let it define a starting sector of 1. Is there someway I could change the starting sector to 1 or do I have to preclear again?

 

I am certain I have seen a similar post but I cannot find it...

 

Thanks in advance for your help.

A 3TB drive MUST use a GPT partition which starts at sector 1.  63 or 64 are only used for drives < 2.2TB in size with a MBR partitioning scheme.  You have nothing to fix.
  • Author

I know you can do this, just not sure if it works with 3TB drives (I know it works for < 2.2TB drives):-

-C 63    = convert an existing pre-cleared disk to use sector 63 as a
                  starting sector.
-C 64    = convert an existing pre-cleared disk to use sector 64 as a
                  starting sector.

 

Direct copy and paste off the preclear help page (E.G. when you run the script with no parameters).

Thanks, now i remember where I had seen it before...

 

A 3TB drive MUST use a GPT partition which starts at sector 1.  63 or 64 are only used for drives < 2.2TB in size with a MBR partitioning scheme.  You have nothing to fix.

 

I didnt know that. I have precleared one more 3TB HD but I did not notice that. Thanks for the info.

Hi everyone,

I precleared a 3TB HD and by mistake I let it define a starting sector of 1. Is there someway I could change the starting sector to 1 or do I have to preclear again?

 

I am certain I have seen a similar post but I cannot find it...

 

Thanks in advance for your help.

You did not make a mistake.

A "protective" partition is defined to "fool" older utilities that the disk is entirely allocated.  That protective partition starts at sector 1.  The actual GPT partition unRAID will use starts at a 4k boundary.  You do not need to do anything to "fix" it, as it is not a mistake.

 

The "-C" option, if it worked for your disk at all, would only break the partitioning.  (I doubt it will allow you to do anything, as it checks for a proper MBR preclear signature first)

 

Joe L.

If you try to use the -C option on a precleared disk > 2.2TB, you should see this:

========================================================================1.13

==

== DISK /dev/sdX IS PRECLEARED with a GPT Protective MBR

== Conversion not possible.  All GPT partitions are automatically 4k aligned.

==

===========================================================================

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