Track/Cylinder allignment on GPT disk

Beeblebrox

Beeblebrox

I have done a considerable amount of searching and reading but cannot locate a satisfactory answer about partitioning to track boundary on GPT:
* Is track & cylinder allignment important in FreeBSD? (I assume yes or is it more important in WÄ°n/Linux)
* Is it important on GPT disks? (I assume yes or is it more an MBR thing)
* Using gpart -a does not necessarily allign to track from what I can tell, and a script to calculate must be used (see aragon)... Really? That hard? Parted under Linux makes it way easier than gparted if you are going to need scripts etc.

I have a headache now so I'll stop trying to figure it out.
 
Aligning MBR partitions to cylinder boundaries is an ancient legacy thing from the early days of MS-DOS, when the geometry reported by a disk actually reflected its internal physical layout.

It simply has no relevance in this age of Logical Block Addressing. I don't understand why FreeBSD even warns about incorrectly aligned partitions any more.

It certainly isn't relevant for GPT partitioning.
 
Go back to whoever suggested that aligning to tracks was still necessary--or even possible--and ask them why. Then ask them how to pull it off with a drive with variable geometry, where the outer tracks have more sectors. Then ask where to get a drive that isn't variable geometry.

Sector alignment, OTOH, is a different matter. When most new drives have 4K sectors but lie and pretend to have 512-byte sectors, it can make a big performance difference if aligned to even multiples of 4K.
 
@aragon & @wblock:
But in "general" terms for ZFS on GPT disk running FreeBSD-9, you would agree that cylinder alignment is insignificant / ancient?
 
The only alignment issues you need to worry about are if you are using Advanced Format drives (because they lie to the OS about their sector size). But it's a totally different issue than your original question, just thought I'd chip in in case you were getting the two confused...

ta Andy.
 
@ wblock: Thanks Warren, you're the man!
Then ask where to get a drive that isn't variable geometry.
Click to expand...
answer: Solid-state device...
This, of course, is a troll answer and has nothing to do with my original question :)

Also, thanks AndyUKG for the input.
 
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