On 10/23/2014 09:05 PM, Steven Haigh wrote:
On 24/10/2014 1:59 PM, Orion Poplawski wrote:
On 10/22/2014 03:23 PM, Steven Haigh wrote:
Hi all,
I'm wondering - I'm looking to simplify my Xen DomU installation via a
kickstart file...
As my Xen config has /dev/xvda - which should be formatted as ext4 and
used as / - is there any options that I can achieve this?
Just about everything I've stumbled across does partitioning first - and
not the entire disk. Without supplying a kickstart file, the installer
will bail saying no disks found.
It's been this way for MANY years, but I heard rumours of a magical
kickstart option - but I can't seem to find it...
What do you have against partitioning the disk? Loosing the 512-bytes
for the partition table?
On some setups it can cause major write degradations in the virtual machine.
If you can imaging the disk being set up in 4Kb clusters - which LVM
then adheres to - but on the DomU disk with a partition, the alignment
for partition data is now 0 + 512 bytes instead of 0.
This means a write of 4Kb would write two sectors to the physical disk
(first being 512 bytes + 4Kb, the second being the 512 bytes that give
us an offset).
In lame ASCII art, this means:
Plain Disk:
0-----------512-----------1024-----------1536-----------2048 etc
Whole disk write:
----------------------------------------------------------> to 4Kb
Partitioned disk write:
[ part tbl ]--------------------------------------------> to 4Kb + 512
bytes
Its good to get your sectors aligned.... Especially when its on a RAID
backend that also has a stripe size as well...
Hmm, that is an issue. I assume you've tried:
part / --onpart /dev/xvda
You may also be able to partition in %pre manually with GPT or dos with
your desired alignment.
Having tried using full disk for things like md raid and lvm in the past
an gotten burned by loosing most autodetection I've given up on not
partitioning.
--
Orion Poplawski
Technical Manager 303-415-9701 x222
NWRA/CoRA Division FAX: 303-415-9702
3380 Mitchell Lane [email protected]
Boulder, CO 80301 http://www.cora.nwra.com
