JP Vossen on 15 Nov 2008 12:04:54 -0800


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Re: [PLUG] Your recommendations


 > Date: Sat, 15 Nov 2008 13:05:00 -0500
 > From: Ugarit Ebla <ugaritebla@gmail.com>
 >
 > Thank you all for your assistance.
 >
 > Please bear with me.  I'm a complete novice when it comes to RAID and
 > LVM.

It's tricky.  I learned the little I know from messing with it in 
VMware, and documenting what I did.


 > Do I first make each partition a RAID then LVM or the other way
 > around?

That's why I sent that step-by-step guide in my first reply.  I 
understand that it looks like so much gibberish, but if you boot up the 
alternate installer CD, get into the partitioner, and start doing it, it 
will hopefully make sense.

Failing that, could you bring the unit to the PLUG W meeting on Monday 
(http://www.phillylinux.org/locations/fnis.html)?  We could collectively 
take a shot at it during the 7-8 misc. time before the preso.  Bringing 
printouts of these emails might help too.


 > Do I do this on each drive?

Not quite.  At a high level you do something like this:

I'm trying to *mirror* so that disks 0+1 are one side of the mirror and 
2+3 are the other side.  So the setup on 0 == 2 and 1 == 3.

	What				dsk0     1     2     3
	------------------------	----  ----  ----  ----
	physical volume for RAID	256M        256M
	physical volume for RAID	(rest rest) (rest  rest)

"Configure Software Raid"
     "Create MD devices"
	Create /boot RAID outside LVM	256M        256M
	"physical volume for LVM"	(rest rest) (rest  rest)
		(The steps above are where you pair the sides of the
		mirrors, 0,1 and 2,3.)

Configure the LVM
     Create volume group, name = vg_hostname
	Create logical volume
		lv_root   # /       30 GB
		lv_var    # /var   100 GB
		lv_home   # /home  100 GB
		lv_tmp    # /tmp     5 GB
		lv_swap_1 # swap    10 GB

You had 1G for /boot, I used 256M above, and kept /boot outside of LVM. 
  I think 1G is way overkill, but given disk sizes, whatever.  I also 
think 5G might be a bit small for /tmp.  10 or 20 might be better, just 
in case, since you have the space.

When you finish, your partitioner screen should look something like this 
(I'm winging this):

     LVM VG vg_hostname, LV lv_root - 30 GB Linux device-mapper
           #1   30 GB   f ext3       /
     LVM VG vg_hostname, LV lv_var  - 100 GB Linux device-mapper
           #1   100 GB   f ext3       /
     LVM VG vg_hostname, LV lv_home - 100 GB Linux device-mapper
           #1   100 GB   f ext3       /
     LVM VG vg_hostname, LV lv_tmp  - 5 GB Linux device-mapper
           #1     5 GB   f ext3       /
     LVM VG vg_hostname, LV lv_swap_1 - 536.8 MB Linux device-mapper
           #1 nnnn MB   f swap       swap
     RAID1 device #0 - 254.9 MB Software RAID Device
           #1 254.9 MB   F ext3       /boot
     RAID1 device #1 - nnnn GB Software RAID Device
           #1   8.3 GM   K lvm
     SCSI3 (0,0,0) (sda) - 8.6 GB VMware, VMware Virtual...
           #1 primary  255.0 MB B K raid
           #2 primary   nnnn GB   K raid
     SCSI3 (0,1,0) (sdb) - 8.6 GB VMware, VMware Virtual...
           #1 primary   nnn  GB B K raid
     SCSI3 (0,2,0) (sdc) - 8.6 GB VMware, VMware Virtual...
           #1 primary  255.0 MB B K raid
           #2 primary   nnnn GB   K raid
     SCSI3 (0,3,0) (sdd) - 8.6 GB VMware, VMware Virtual...
           #1 primary  nnnn  GB B K raid


It looks like Ubuntu might use GRUB2 after all, so maybe keeping /boot 
out of LVM is force-of-habit.  But conservative and proven methods 
aren't a bad thing. :-)

Good luck,
JP
----------------------------|:::======|-------------------------------
JP Vossen, CISSP            |:::======|        jp{at}jpsdomain{dot}org
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