vinum or gvinum

[Tomas Palfi]

Stijn,

I think I am almost there as the disks are now sincing.  Thank you for
your help, it has been really appreciated.  I am still going fiddle with
the mirror with the gvinum.

Tomas
--
tp




-----Original Message-----
From: Stijn Hoop [mailto:stijn at win.tue.nl] 
Sent: 09 September 2005 12:12
To: Tomas Palfi
Subject: Re: vinum or gvinum

Hi,

On Fri, Sep 09, 2005 at 12:04:42PM +0100, Tomas Palfi wrote:
> Thanks for this update, I am configuring the gmirror as per the
> instructions, however, there is one thing which bothers me a bit.
> 
> bsdlabel -e /dev/mirror/gm0s1 when editing the new layout, it
> advices me to start "a" partition at offset 16, and "c" as per default
> at offset 0.  do I have to retain the offset 16 for the "a" partition
> where my root is located or can i have another offset + 16 and start
> swap at 0 offset?  In this case the swap would start with offset 0 as
> "b".

Sounds fine. In the past there have been troubles with old BIOSes not
booting from root partitions that were located "far" on the disk (>2G
I believe). I don't think that limitation exists anymore, but keep it
in mind. Other than that, FreeBSD will be happy.

> this is my exiting layout on /dev/da0s1
> 
> a: 10485760  10485760   that's /root
> b: 10485760 	  0		  swap
> c: 143363997	  0
> d: 20911520  20911520          /home
> e: 14680064  41943040		 /tmp
> f: 14680064  56623104		 /var
> g: 72060829  71303168		 /usr/local
> 
> 
> and this is what I would lay it as on the /dev/mirror/gm0s1
> 
> |-|-----|-----|-----------|--------|--------|--------------------|
> 16 swap  /root   /home       /tmp     /var       /usr/local
> 
> 
> 
> a: 10485760  (10485760 + 16)  that's /root
> b: (10485760 - 16)	  16		  swap
> c: 143363997	  0
> d: 20911520  20911520          /home
> e: 14680064  41943040		 /tmp
> f: 14680064  56623104		 /var
> g: 72060829  71303168		 /usr/local
> 
> in this case the swap would be offset by those 16??

Yes, I would definitely offset things by 16 sectors. I don't really know
what's stored there but you don't lose much and it probably makes sense.

Also keep in mind that you need to make sure that /dev/ad0s1 does NOT
cover the ENTIRE disk, but rather leaves a few sectors spare at the
end. This is to make sure that gmirror does not confuse /dev/ad0 and
/dev/ad0s1 as providers for the mirror (it stores it's metadata in the
last sector). All of this is described in the article, although maybe
not very clear. Note also that by default, FreeBSD leaves a few sectors
spare when runnign fdisk, so it's not an issue most of the time unless
you 'dangerously dedicate' your disks.

Hopefully it'll all work out today ;-)

--Stijn

-- 
It's harder to read code than to write it.
		-- Joel Spolsky,
	
http://www.joelonsoftware.com/articles/fog0000000069.html

PRIVACY & CONFIDENTIALITY

This e-mail is private and confidential.  If you have, or suspect you have received this message in error please notify the sender as soon as possible and remove from your system.  You may not copy, distribute or take any action in reliance on it. Thank you for your co-operation.

Please note that whilst best efforts are made, neither the company nor the sender accepts any responsibility for viruses and it is your responsibility to scan the email and attachments (if any).

This e-mail has been automatically scanned for viruses by MessageLabs.