[lug] lvm + raid

Hugh Brown hugh at math.byu.edu
Mon Sep 22 04:12:46 MDT 2003

On Mon, 2003-09-22 at 03:53, Sean Reifschneider wrote:
> On Mon, Sep 15, 2003 at 09:39:04PM -0400, Hugh Brown wrote:
> >Is doing lvm on top of raid 5 (3ware card) a bad idea?
> Definitely not.  When you add that second card, with another 300GB, you
> can then add it to the first logical volume and extend the partition to
> 600GB using something like ext2resize, so a single partition covers both
> drives.  Yay!

The 3-ware card I have is capable of doing 8 drives.  The case is only
capable of 6 drives (one is a 40 gig system disk and the others are all
200g).  So, I have ~800g available to me in a raid 5.  I opted to break
it up in to a few more partitions.  It was kind of weird for me to think
that I have a box that would have a terabyte of disk available (if it
weren't for raid 5).  Of course this box is going to be a collect all
for backing up all the other servers company wide, so it probably won't
take more than a couple of years to fill the thing up.

> >Also, should I expect a mkfs on a 300gig partition to put the load up
> >around 3?
> It certainly could.  If you are booted off a partition on that same
> drive, I/O on the other partitions may have to wait until some of the
> I/O related to the mkfs gets flushed.
> I didn't notice on the new RAID array I just built at home.  I wasn't
> really so impatient that I went over to another window and checked the
> system load during the 30 or 45 seconds it took to mkfs on my 300 or
> 700GB partitions...

I had to wait more than 30 or 45 seconds (at least I think I did).


> Sean
> (JFS, baybee)

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