Re: [PLUG] Questions on LVM raid...

[James Barrett <jadoba@jadoba.net>]

Doug Crompton wrote:
> Ok I am brining up my new system and I want to run LVM and raid 1 but I am
> not clear on some things....
>
> I will have the following partitions -
>
> /, /boot, /usr, /home, /var, and swap.

Perhaps add /tmp as well.

> I have read the raid how-to and the lvm howto but neither seems to give
> good combination examples or explanations of the subject.
>
> Some questions...
>
> I had planned on /boot being outside of lvm in it's own partition.
>
> So I would make two primary partitions - /boot and the container for lvm ?
>
> The rest of the filesystems would be in lvm
>
> Should swap be in lvm?

It can be done. If you wanted to put in more RAM, you might want to 
increase your swap size as well, so keeping it in the LVM might be a 
good choice in that scenario. The thing is, your LVM will be on top of a 
RAID1 array... Why would you want or need redundancy for swap? It would 
just waste a lot of space.

A better option might be to span the swap partitions equally over 
multiple disks in non-lvm partitions, completely outside of the RAID 
array. This will save a considerable amount of disk space.

> Then I would make two raid 1 partitions - md0 for /boot an md1 for lvm.
>
> Is this a proper? good? method.

Why not just have md0 be / (including /boot), and then have md1 be lvm?

> Another question I have is filesystems. Suse defaults to ext3, with a note
> that it is more reliable I believe. I am sure there are many differing
> opinions on this. I have been using ext3 in my old server without
> problems for years. It seems reiserfs is often used. Any thoughts?

ext3 is good for small partitions, not good for bigger ones. Definitely 
ext3 for /root; if you have a /tmp partition (which is not a bad idea) 
then I would use ext2 as it does not need journaling. For everything 
else, like Matthew said, XFS or JFS is a better solution.

> In the above scenerio, assuming it is correct, I assume that the only
> formatting to fs that is done is when lvm is created?

I guess you want to know if you would have to re-format if you were to 
resize, in which case, no: http://tldp.org/HOWTO/LVM-HOWTO/extendlv.html

> Doug
>
>
> ****************************
> *  Doug Crompton	   *
> *  Richboro, PA 18954	   *
> *  215-431-6307		   *
> *		  	   *
> * doug@crompton.com        *
> * http://www.crompton.com  *
> ****************************
>
>
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