Trying to RAID0 dual boot, need help with "simple" math.

2009-08-21 13:29:17

#1

Sydney: 2λчиэλ; +783|7104|Reykjavík, Iceland.

Each time you run the dd command it will tell you how many bytes were generated. If your dd output has the metadata header lined up exactly, then the number of bytes generated is also the exact offset where the metadata lies relative to the end of the disk. You just need to use the sector size from the fdisk command to complete the calculation. So if my metadata lined up exactly at skip=312499089 and the dd command dumped 466432 bytes then: 312499089 minus ( 466432 divided by sector size of 512k/sector ) = 911 sectors from the end of the disk

I just can't understand how he can get 911 out of those numbers...can anyone help me?

My respective numbers:
skip=625140333
dd dumped 1082880 bytes

Endless karma if you can help me.

Full howto:
https://help.ubuntu.com/community/FakeRaidDebug

2009-08-21 13:37:08

#2

Brasso: member; +1,549|6891

( 466432 divided by sector size of 512k/sector ) makes .911 if that helps

"people in ny have a general idea of how to drive. one of the pedals goes forward the other one prevents you from dying"

2009-08-21 13:39:34

#3

Sydney: 2λчиэλ; +783|7104|Reykjavík, Iceland.

466432 divided by 512 makes 911

How come I didn't see that earlier...

2009-08-21 13:40:37

#4

Brasso: member; +1,549|6891

Sydney wrote:
466432 divided by 512 makes 911

How come I didn't see that earlier...

whoops i assumed 512k meant 512000

"people in ny have a general idea of how to drive. one of the pedals goes forward the other one prevents you from dying"

2009-08-21 14:43:16

#5

Sydney: 2λчиэλ; +783|7104|Reykjavík, Iceland.

Bah, turned out the problem wasn't Linux, but Windows (as usual). The Windows installation must have fubared up the RAID setup.

Going to try to install Linux first, then Windows and see how it goes.

2009-08-21 15:21:55

#6

Sydney: 2λчиэλ; +783|7104|Reykjavík, Iceland.

So far so good, got Linux working on the RAID, now I just need to see if Windows wants to install.

2009-08-21 15:24:26

#7

FloppY_: +1,010|6546|Denmark aka Automotive Hell

Sydney wrote:
So far so good, got Linux working on the RAID, now I just need to see if Windows wants to install.

in my experience it is never good installing windows last :S

That causes the Linux Bootmanager to get whiped in favor of the Windows one :E

Your thoughts, insights, and musings on this matter intrigue me

2009-08-21 15:32:43

#8

chuyskywalker: Admin; +2,439|7108|"Frisco"

My next system is going to be Ubuntu/Win7 -- but I'm just going to get separate drives. Seems like way less hassle to use the bios "select a drive" menu than trying to get windows/linux to play nice on the same device(s).

2009-08-21 15:34:32

#9

Sydney: 2λчиэλ; +783|7104|Reykjavík, Iceland.

FloppY_ wrote:
Sydney wrote:
So far so good, got Linux working on the RAID, now I just need to see if Windows wants to install.
in my experience it is never good installing windows last :S

That causes the Linux Bootmanager to get whiped in favor of the Windows one :E

Not at all, I just have to reinstall GRUB after installing Windows, that's what I did on my laptop.

And chuy, I'm only doing this as I want the increased speed of RAID0 on both OSes

edit: Huzzah! The Windows 7 install started! Now I just have to see how grub will react to booting into a RAIDed windows...

Last edited by Sydney (2009-08-21 15:39:29)

2009-08-21 15:42:47

#10

chuyskywalker: Admin; +2,439|7108|"Frisco"

Sydney wrote:
And chuy, I'm only doing this as I want the increased speed of RAID0 on both OSes

For sooth (or something), but I just plan on going SSD anyway, so I don't think RAID will gain me much when I do the upgrade*. My current machine is running 4 36gb raptors in raid 0. It's nice, but I've never really felt it made much of a real difference -- a second or two here and there for the far greater MTBF doesn't really play out for me.

* Unless it was RAID SSD, lolerdrool!

2009-08-21 15:49:34

#11

Sydney: 2λчиэλ; +783|7104|Reykjavík, Iceland.

chuyskywalker wrote:
Sydney wrote:
And chuy, I'm only doing this as I want the increased speed of RAID0 on both OSes
For sooth (or something), but I just plan on going SSD anyway, so I don't think RAID will gain me much when I do the upgrade*. My current machine is running 4 36gb raptors in raid 0. It's nice, but I've never really felt it made much of a real difference -- a second or two here and there for the far greater MTBF doesn't really play out for me.

* Unless it was RAID SSD, lolerdrool!

Made me jizz my pants.

Booting into W7 now, it's looking fine, now the final stage, getting GRUB to play along with both OSes.

2009-08-21 15:51:19

#12

Bertster7: Confused Pothead; +1,101|6842|SE London

I maintain that the best way to get good speeds economically is to have way more space than you need. Drives with a high percentage of free space are fast. Keeping the data all on the outer bit of the platters leads to better access times, since that's where the head starts reading and better transfer speeds since the outer bit spins faster.

Typically makes more difference than RAID0 (which can often negatively impact access times) in normal usage scenarios.

2009-08-21 16:02:27

#13

Sydney: 2λчиэλ; +783|7104|Reykjavík, Iceland.

Bertster7 wrote:
I maintain that the best way to get good speeds economically is to have way more space than you need. Drives with a high percentage of free space are fast. Keeping the data all on the outer bit of the platters leads to better access times, since that's where the head starts reading and better transfer speeds since the outer bit spins faster.

Typically makes more difference than RAID0 (which can often negatively impact access times) in normal usage scenarios.

I'm raiding two 320GB drives. 320GB for Ubuntu, 320GB for Windows. I don't expect to use more than 50GB on each. I have 2.2 TB of storage which I fill up, while keeping the OS disks pretty free.

2009-08-21 16:15:18

#14

Sydney: 2λчиэλ; +783|7104|Reykjavík, Iceland.

SWEET JESUS IT WORKS!

Ubuntu 9.04 and Windows 7 Ultimate running together on the same RAID0

I WIN FREE INTERNETS!

BF2S Forums Trying to RAID0 dual boot, need help with "simple" math.

Sydney wrote:

Sydney wrote:

FloppY_ wrote:

Sydney wrote:

Sydney wrote:

chuyskywalker wrote:

Sydney wrote:

Bertster7 wrote:

Board footer