[CentOS] Re: Anaconda doesn't support raid10

Wed May 9 15:40:42 UTC 2007
Ross S. W. Walker <rwalker at medallion.com>

> -----Original Message-----
> From: centos-bounces at centos.org 
> [mailto:centos-bounces at centos.org] On Behalf Of Ruslan Sivak
> Sent: Wednesday, May 09, 2007 10:36 AM
> To: CentOS mailing list
> Subject: Re: [CentOS] Re: Anaconda doesn't support raid10
> 
> Les Mikesell wrote:
> > Ruslan Sivak wrote:
> >
> >> Yea, I think for these reasons I will use lvm.  I have set up a 
> >> system as follows:
> >>
> >> /boot raid 1 200mb 4 drives no spares (I guess this makes 
> 4 copies of 
> >> the data?)
> >
> > What't the point of putting this on more than 2 drives?
> >
> Well for one thing, if 2 drives fail and it doens't get a chance to 
> rebuild, then I still have 2 good drives.  Another thing is 
> if a drive 
> fails and the spare is in the wrong location, and the spare 
> becomes the 
> boot drive, it won't be able to boot, but if all 4 drives are 
> copies of 
> each other, then everything is well and good. 
> >> / 10gb on lvm
> >> /data 50gb on lvm
> >> /backup 250gb on lvm
> >>
> >> rest of space left free to allow for resizing and adding of 
> >> partitions with lvm
> >>
> >> I will pull out a drive tommorow and see how resilient 
> this is.  Does 
> >> this sound like a good solution?
> >
> > It is versatile, if you don't know where the additional 
> space will be 
> > needed but don't think mounting it as separate partitions in 
> > subdirectories will be handy.  I forgot to mention the 
> other reason I 
> > like straight RAID1 installs - you can easily clone a 
> machine with all 
> > of its current software  by pulling a drive, booting it in a new 
> > machine and rebuilding the raids on both.
> >
> I don't see why I can't pull out 2 drives out of this install (like 1 
> and 3), put them into another machine and let it rebuild itself. 

I figured out how to create interleaved LVs on the install, it is a
little PITA though.

Start the install, create all your RAIDs and VGs and LVs as before, and
move on to the next step, once they have been committed and formatted
before the package installation, reboot and start over.

Then when you get to the partitioning section, select "Custom" and go
back to that screen.

Then jump to tty2 (or serial console) and start the shell, go into lvm,
by typing 'lvm'.

Within lvm you will need to remove the existing LVs with:

lvremove <VGname>/<LVname>

for each LV created, swap, root, etc.

Then re-create the LVs with:

lvcreate -L <size in MB>M -i 2 -n <LVname> <VGname>

Do it for each LV, the -i 2, says interleave (strip) it across 2 PVs.

Once that's done you can then hit the <Back> button and then go back
in to 'Custom' to have it refresh the setup. Just choose to format
each in their types and move along.

Remember to choose 'Custom Layout' each time so you don't fubar your
hard work!

-Ross

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