Samba and RAID 1 using gmirror on 2 new disks

Jerry McAllister jerrymc at
Fri Apr 20 20:07:37 UTC 2007

On Fri, Apr 20, 2007 at 12:39:28PM -0700, L Goodwin wrote:

> Thanks for the steps, Laszlo. I got as far as creating a freebsd slice on da1 (both da1 and da2 have been low-level formatted).
> Now I have two questions:
> 1) When creating the slice on da1, I specified to use the entire disk, but there are 2 unused sections -- one before and one after the new slice (please see attached file). Should I start over and specify a smaller size? What size should I specify?:'
> 2) About creating partitions on da1: You specified to add partitions to the slice (/dev/da1s1a, /dev/da1s1b,/dev/da1s1c etc.). 
> Please note: 
> a) The entire FreeBSD filesystem is on da0. 
> b) I want to use the entire da1 disk for users on Windows clients to store files/documents on. I also want the mirror disk (da2) to be backed up regularly.
> Do I need to create more than one partition on da1? What are the requirements for naming partitions in this situation?

Probably there is some confusion.    
If you alredy have your FreeBSD stuff on da0 and only want to put
the windows stuff on da1, then you don't need it divided up in
to all the extra partitions.   

If you want Windows clients to use it, do you plan to run Samba?     
If not, maybe you should just make the disk a Windows disk, but make 
it FAT32 so FreeBSD can both read and write it.   If it will be the 
store for Samba, then forget this comment.

As for the unused bit before and after the slice, if I understand what
you are pointing to, that is normal.   It is now normal to just skip
the first whole track where an MBR might be written rather than just
one sector.   That is the 63 extra blocks at the beginning.
Then, fdisk will ignore trailing stuff that doesn't conveniently fit
in to the addressing scheme.    Neither part amounts to much actual
disk space by today's standards so it is just ignored.   If you are
going to make a mirror, then try to get the two slices to come out
to the same size.  Otherwise don't worry about it.


> Thanks!
> Nagy László Zsolt <nagylzs at> wrote: *L Goodwin wrote:
>  >
>  > Both assume you only have 2 drives and want to mirror the drive 
> containing FreeBSD. I only want to mirror the data drive da1, and would 
> appreciate a concise set of steps for doing this right the first time.
> 1. First of all, you should install the base system on da0 and boot it. 
> (Leave da1 and da2 untouched)
> 2. Create a slice on da1 ("fdisk"). The name of the new slice will 
> probably be "da1s1". (You will find this inside sysinstall) I found that 
> sometimes I had to use a bit smaller slice than the available space, 
> because equally looking disks are not always equal. (Not kidding!)
> 3. Use disklabel editor to add partitions to the slice 
> (/dev/da1s1a,/dev/da1s1b,/dev/da1s1c etc.) and format them with newfs as 
> needed.
> 4. Change loader.conf, add this line:
> geom_mirror_load="YES"
> 5. Execute these:
> gmirror load
> gmirror label -v -b round-robin gm0 /dev/da1
> 6. Carefully rename all references in /etc/fstab
> /dev/da1s1X becomes /dev/mirror/gm0s1X      (where X can be a,b,c,d etc.)
> 7. Reboot
> 8. Check your mirror with "gmirror list" and "gmirror status", and see 
> if your filesystems are mounted with "df".
> 9. Add da2 to your mirror with this command:
> gmirror insert gm0 /dev/da2
> Please ask others, as I did not try this and I'm not 100% sure it will 
> work. But I think it should.
> Best,
>    Laszlo
> *
> ---------------------------------
> Ahhh...imagining that irresistible "new car" smell?
>  Check outnew cars at Yahoo! Autos.
Content-Description: 2793854837-FDISK.txt
> Prepare disks da1 and da2 (after low-level format):
> Run FDISK from systinstall:
> DISK name: da1                                              FDISK Partition Editor
> Disk Geometry: 1115 cyls/255 heads/63 sectors = 17912475 sectors
> Offset      Size(ST)    End      Name      PType      Desc      Subtype      Flags
> 0           17916240    17916239 -         12         unused    0
> After Create slice (size = 17916240, type = 165):
> Offset      Size(ST)    End      Name      PType      Desc      Subtype      Flags
> 0           63          62       -         12         unused    0
> 63          17912412    1912474  da1s1     8          freebsd   165
> 17912475    3765        17916239 -         12         unused    0

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