Align a GPT partition
Guillermo G. Lovato
i need to partition a 5.8TB RAID5 array in one piece in Win2003R2.
i've followed diskpart info from ms support site but it never covers GPT
partition and i can't use MBR as it tops @2TB.
So i have a blank GPT drive with NO partitions, i run:
wmic partition get BlockSize, StartingOffset, Name, Index
BlockSize Index Name StartingOffset
512 0 Disk #0, Partition #0 16384
512 0 Disk #1, Partition #0 17408
Then i do a list partition in diskpart
DISKPART> list partition
Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 Dynamic Reserved 1024 KB 17 KB
Partition 2 Reserved 127 MB 1041 KB
The stripe size is 64KB, but i have those 2 hidden space-eating partitions
at the beginning of the drive and i can't align them correctly, i've tried
align=1024, 64, 128 and the results are awful.
do i use 2048?, or the offset align is relative to the last partition end?
how do i align this?
thanks in advance
Isaac Oben -MCSE, MCITP
Depending on your hardware, you can configure and align partition at the
startup console. Look through the console when the server is booting and
look for the right key to hit that will take you to configuration etc.
Isaac
"Guillermo G. Lovato" <glo...@mast.com.ar> wrote in message
news:OzIw1zPm...@TK2MSFTNGP05.phx.gbl...
Guillermo G. Lovato
nothing to do with the alignment process, only with raid volume creation,
what i need to know if what offset do i use with diskpart to align a GPT
partition.
"Isaac Oben -MCSE, MCITP" <isaac...@nospam.gmail.com> wrote in message
news:uluodRcm...@TK2MSFTNGP06.phx.gbl...
ian.b...@calderdale.gov.uk
> What configuration?, you mean the RAID controller BIOS?, if so, it has
> nothing to do with the alignment process, only with raid volume creation,
> what i need to know if what offset do i use with diskpart to align a GPT
> partition.
>
>
>
>
> > Guillermo,
>
> > Depending on your hardware, you can configure and align partition at the
> > startup console. Look through the console when the server is booting and
> > look for the right key to hit that will take you to configuration etc.
>
> > Isaac
>
> >news:OzIw1zPm...@TK2MSFTNGP05.phx.gbl...
> >> Hello,
> >> i need to partition a 5.8TB RAID5 array in one piece in Win2003R2.
> >> i've followed diskpart info from ms support site but it never covers GPT
> >> partition and i can't use MBR as it tops @2TB.
>
> >> So i have a blank GPT drive with NO partitions, i run:
> >> wmic partition get BlockSize, StartingOffset, Name, Index
> >> BlockSize Index Name StartingOffset
> >> 512 0 Disk #0, Partition #0 16384
> >> 512 0 Disk #1, Partition #0 17408
>
> >> Then i do a list partition in diskpart
> >> DISKPART> list partition
>
> >> Partition ### Type Size Offset
> >> ------------- ---------------- ------- -------
> >> Partition 1 Dynamic Reserved 1024 KB 17 KB
> >> Partition 2 Reserved 127 MB 1041 KB
>
> >> The stripe size is 64KB, but i have those 2 hidden space-eating
> >> partitions at the beginning of the drive and i can't align them
> >> correctly, i've tried align=1024, 64, 128 and the results are awful.
> >> do i use 2048?, or the offset align is relative to the last partition
> >> end?
>
> >> how do i align this?
>
>
> - Show quoted text -
Hi,
I had a similar problem this week. But when I looked at the offset
for the first 2 partitions, they already add up to 128MB, which is a
multiple of 64KB. So I guessed I didn't need to set any extra
alignment (I just wanted to optimise disk I/O). Can anybody confirm
that alignment isn't necessary for GPT disks?
Thanks
Ian
ian.b...@calderdale.gov.uk
>
> - Show quoted text -
To answer my own question - this link
http://sqlblogcasts.com/blogs/grumpyolddba/archive/2008/04/03/disk-partition-alignment-sans-and-diskpart.aspx
was useful and pointed to MS KB300415 which says that "on GPT disks
the size or offset parameters are rounded to sector alignment" (not
like MBR disks, which are rounded to cylinder alignment). So on GPT,
it looks like it's already done for us!
Ian