[CentOS] Analyzing the MBR

Thu Jun 5 22:06:46 UTC 2014
John R Pierce <pierce at hogranch.com>

On 6/5/2014 2:50 PM, Les Mikesell wrote:
> New bigger disks may use 4k physical sectors but report 512 for
> backwards compatibility.  If you don't write 4 contiguous sectors it
> has to read, wait for the disk to spin back around, then write,
> merging in what you did write.  Which means writes will be very slow
> if your partitions are not aligned on 4k boundaries. I haven't had to
> deal with many of these yet so I've mostly just installed gparted from
> epel and used its defaults rather than doing the math myself.

some new disks even report they are 4K and allow 4K sector operations, 
which file systems like XFS support natively.   This is going to be 
increasingly common going forwards.

[btw, thats 8 consecutive 512B sectors for 4K]

john r pierce                                      37N 122W
somewhere on the middle of the left coast