[CentOS] fdisk partition table plus sign

William L. Maltby CentOS4Bill at triad.rr.com
Mon Apr 21 17:42:32 UTC 2008


On Mon, 2008-04-21 at 19:31 +0200, Kai Schaetzl wrote:
> William L. Maltby wrote on Mon, 21 Apr 2008 12:06:06 -0400:
> 
> > As to loss, maybe yes. When you allocate using multipliers, (10GB,
> > 100MB, etc.) the bytes per cylinder is used as a divisor. This *may*
> > leave some part of a cylinder unused at the end. With todays drive
> > sizes, even anal me doesn't worry about it anymore.
> 
> well, I was wondering about that when I wanted to duplicate a partition 
> and I wasn't able to get exactly the same block size in fdisk, neither 
> with size in GB nor with last cylinder.

As long as the files system does not map beyond the end of a partition
on the target drive, you'll be OK. If the drive geometry *appears* the
same and your target partition(s) are at leaset as large as the source
partitions, you should be OK.

Given the above, the only ill-effects I've seen are intangible. As when
sfdisk gives you a warning about the geometry appears to have been
created for one C/H/Spt but this drive seems different.

Since we all do LBA now (don't we?), no harm.

If you want to be absolutely sure, "man sfdisk". This will let you have
complete control, even allocating by sector count. It will let you save
a "map" of the current drive and apply it to a new drive.

If you are fairly new to this level of stuff (... hmm, even if not),
please have good backup/recovery plans and data if you are affecting
production drives.

> 
> Kai
> 

HTH
-- 
Bill




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