Re: [Maybe Spam] LVM questions (RHEL3) and considerations for LVM2 (in future RHEL4?)

[Al Tobey <albert tobey priority-health com>]

On Wed, 2004-06-09 at 13:08, Patrick Bakker wrote:
> Hi.
> 
> I have 3, 36 GB, SCSI hard drives in a RAID 5 configuration managed by a
> battery-backed Dell PERC RAID controller. I have 1 hot-spare hard drive.
> 
> I plan to store a database for my J2EE application and serve
> high-resolution
> image files over a SAMBA share on this effective 72 GB. At present I
> have an abundance of storage space for the current size of the database
> and the number of pictures so I am not sure how to best allocate out the
> space.
> 
> I am wondering if it is smart to make some basic partitions:
> 	boot (100 MB partition)
> 	root (1 GB partition)
> 	var (1 GB partition)
> 	tmp (1 GB partition)
> 	swap (2 GB partition = 2 GB of RAM)
I've been using LVM1 on all my production systems for a coule years
now.  I currently create a root partition of 512MB, then an LVM
partition consuming all the rest of the space - enough for swap, then
the third, swap.   I have set up systems (i.e. my laptop) to have swap
on LVM, too. So, on my DL360's:
   root (512MB)
   LVM  (15.5GB)
   swap (2GB)
Then:
/dev/vgroot/lv_home on /home type ext3 (rw)
/dev/vgroot/lv_opt on /opt type ext3 (rw)
/dev/vgroot/lv_tmp on /tmp type ext3 (rw)
/dev/vgroot/lv_usr on /usr type ext3 (rw)
/dev/vgroot/lv_usrlocal on /usr/local type ext3 (rw)
/dev/vgroot/lv_var on /var type ext3 (rw)
/dev/vgroot/lv_web on /web type ext3 (rw)
/dev/vgroot/lv_ora on /ora type ext3 (rw)

/boot was a hack for old hardware with BIOS that couldn't understand
large (>8GB IIRC) hard drives.   This should not be necessary on modern
hardware, and besides having your root volume in the first 512MB still
works around the BIOS bug.

>  and use LVM to create some volume groups:
> 	home (1 GB)
> 	usr (8 GB)
> 	database (8 GB)
> 	pictures (30 GB)
>  for a total of:
> 	50 GB
>  leaving 20 GB for future expansion.
> 
> I have heard that there are some incompatibilities between LVM and LVM2.
> Will I have any problems if I use LVM now to upgrade to LVM2 when RHEL 4
> comes out?
The upgrade from LVM1 to LVM2 has been flawless for me.  I've only ever
had trouble with going back to LVM1 after running LVM2 on a VG.

> I have also read that LVM2 is an alternative to EVMS. Is there an LVM2
> equivalent to EVMS console and GUI tools?
I believe LVM2 is only command-line.   I believe you can mix & match
your use of the EVMS and LVM2 tools at will, since they both use the
device-mapper backend.

> And more generally is LVM considered stable enough to resize volume
> groups on a production system?
No problem.  I use this all the time on my production systems.   In
fact, before I went to RHES 3.0 and switched to the ext3 filesystem, I
could resize the volume AND filesystem online (using reiserfs). 
Hopefully, RH will patch ext3 to be online-resizeable soon.  With ext3
you have to unmount the filesystem to make it grow to the size of the
volume.

> 
> ---
> Patrick

-Al Tobey




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