On Friday 14 July 2006 13:39, stan wrote:
> On Fri, Jul 14, 2006 at 11:11:47AM -0400, John Nielsen wrote:
> > On Friday 14 July 2006 10:37, John Nielsen wrote:
> > > On Thursday 13 July 2006 20:24, stan wrote:
> > > > On Thu, Jul 13, 2006 at 04:20:56PM -0400, John Nielsen wrote:
> > > > > On Thursday 13 July 2006 08:34, stan wrote:
> > > > > >  i have a Sun Ultra 40 with 4 500F SATA drives. I plan on using
> > > > > > this machine primarily for a large data storage requirement.
> > > > > >
> > > > > >  What I want is one large /data partition. Given all the choices
> > > > > > for doing this in FreeBSD (software) what's the "best" choice
> > > > > > here? The partio will be shared via SAMBA if that affects the
> > > > > > thhinking here.
> > > > >
> > > > > "Best" really depends on what your needs and goals are. Here's a
> > > > > quick overview of what the choices ARE, based mostly on memory.
> > > > > Corrections and additions welcome. I'll try to make some notes
> > > > > about pros and cons as well.
> > > >
> > > > Thanks for the nice summary.
> > > >
> > > > The data will be backed up nightly, so I'll probably use gstirpe to
> > > > get the maximum capicty. RAID5 would not work very well with 3 x 500G
> > > > (asuuming that I can't use the 500G that I put the system on).
> > >
> > > If that's really what you want to do then here are a couple more tips.
> > > You can't boot from a gstripe volume, and when (not if) one of your
> > > drives goes bad you'll be happier if you only lose your data and not
> > > your entire OS. So plan to partition the drives and use gmirror for the
> > > base OS (since you can boot from a gmirror volume). Make a relatively
> > > small partition (10GB?) at the beginning of each drive. Make a gmirror
> > > volume using two or three of them and install the OS to that volume.
> > > Use the remaining one or two small partitions for swap or utility
> > > partitions. Then make your giant gstripe volume out of the large
> > > partitions on all four drives.
> >
> > Or better yet, make a gvinum RAID5 volume with the four large partitions.
> K, I think I'm convinced. That would give me 1.5TB for my 2TB of physical
> disk.

Roughly speaking.

> Got a pointer to docs on how to install the base OS on a RAID5 config?

I'm not sure you can boot from a RAID5 volume, and it's tricky to boot from a 
gvinum volume at all. I would still recommend partitioning and installing the 
OS to a gmirror volume, and then set up your gvinum RAID5 after the fact.

Unfortunately, sysinstall doesn't grok advanced disk setups very well, so 
you'll have to get started manually.  I would do this:

Download and burn a FreeBSD 6.1 Install CD (disc 1) and boot from it.
Go into "Fixit" mode.
Set up the basic partitions and a degraded gmirror volume (with only one 
member) rom the "Fixit" console. Repeat all of the fdisk and bsdlabel steps 
for each disk, substituting your real disk names for ad0 below:
        fdisk -BI ad0
[repeat for all disks]
        bsdlabel -wB ad0s1
[repeat for all disks]
        bsdlabel -e ad0s1
[manually shrink the 'a' partition (which you'll use as the 'small' one) and 
create a 'd' partition (which you'll use as the 'large' one). Calculator, 
pencil and paper (or their equivalents on another computer) are useful here.]
[repeat for all disks]
        kldload geom_mirror
        gmirror label -b load myrootfs /dev/ad0s1a
[You can replace 'myrootfs' with a volume name of your choosing. Perform this 
step only for the disk the computer BIOS is set to boot from. Do not repeat 
for the other disks.]
        newfs -U /dev/mirror/myrootfs
Exit sysinstall and reboot; boot from the CD again.
Perform a "Standard" install. Mount '/' on the existing ad0s1a (or the device 
name used in the "gmirror label" step). Do not mount or create any other 
partitions (or swap, yet). Perform the remainder of the install as normal.
Reboot after the installation, and remove the CD.
Allow the system to come all the way up to multi-user to be sure there aren't 
any problems.
Log in as root.
Drop back down to single-user:
        shutdown now
Edit /boot/loader.conf and add the line
Edit /etc/fstab. Change the line for / to use /dev/mirror/myrootfs instead 
of /dev/ad0s1a. Add a line like "/dev/ad3s1a none swap sw 0 0" to use the 
small partition on a drive not to be included in the mirror as swap space.
Bring the system up in single-user mode from the boot menu.
Add the additional partition(s) to the mirror set:
        gmirror insert myrootfs /dev/ad1s1a [/dev/ad2s1a]
Wait for the rebuild to complete. You can check the status by typing:
        gmirror status
Allow the system to come all the way up to multi-user. Verify that the mirror 
is being used as the root device and is healthy, and that swap has been 

At this point you will now have a fully functional, mirrored FreeBSD 
installation. Refer to existing [g]vinum documentation for details on setting 
up RAID5. You will use the ad[0-3]s1d devices as members of the array.

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