[ale] Recommendations on mirrored LVM..?

[Keith Hopkins]

Eric Webb wrote:
> I'm working towards putting together a large, cheap disk repository with a 
> little redundancy.  The goal here isn't performance, but more of creating a 
> big chunk'o'disk that is somewhat protected.
> 
> I'm interested in running the LVM code based on experience with it under AIX. 
>  A few questions come up though:
> 
> 1.  ext3 or reiserfs?

I've been using reiserfs for almost 3 years with little problem.  I love it.  I keep reading in the rags that it's "still beta", and I wonder "what under linux isn't permanently beta?"
EXT3 and XFS are both supposedly "more mature".  I don't see how that can be possible for EXT3.

> 
> 2.  How do I mirror the dang thing?  AIX supports lvcopies, which is what I'd 
> like to do, but I don't believe the Linux LVM does.  The only idea I can come 
> up with is to use the raidtools to create a mirrored device, and then feed 
> that device to the LVM code.  Will that work?  Will it work WELL?  Doesn't 
> sound as flexible to me.

   Either use a HW-RAID card, or SW-RAID (MD tools) for fault tollerance.  LVM doesn't do mirroring.  I have / on reiserfs SW-RAID mirrored, and LVM/reiserfs on top of a seperate SW-RAID mirror for /usr, var, opt and tmp on my mail server.  LVM/reiserfs on top of HW-RAID for my file server.
   SuSE 7.3 supported RAID and LVM under the YAST2 graphicall installer, but 7.3's YAST2 is buggy and if you edit anything (LVM) after initially defining it, then YAST2 and your install flakes out by trying to create the PV/VG twice.  I took me 5 tries to get the "magic sequence" right, just last night.  7.1's installer didn't support both LVM & RAID.
   RH7.3 is the only other OS I've tried lately, and it didn't support LVM during the install.

/dev/sda 
/dev/sdb
p0 ext2 /boot	ext2 /local		128M
p1 swap		swap 
		384M
p2 md0		md0	reiserfs / 	512M
p4 md1		md1	(LVM vg00)	rest of disk

vg00: lvusr, lvopt, lvvar, lvtmp (all reiserfs)

(/home is nfs mounted from another server)

Don't use reiserfs for small partitons, like /boot, since it will eat about 25M during the mkfs.
sda and sdb are about the same size disks (4.5G, 4.51G).  md1 ignores the "extra" 0.01G of space of the larger disk.

How did your project turn out?

-- 
Lost in Tokyo,
   Keith



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