[TriLUG] Department server sonfig suggestions please.

[David A. Cafaro]

On Wed, 2004-08-04 at 05:46, Matthew Lavigne wrote:
> On Tue, 03 Aug 2004 21:32:27 -0400, David A. Cafaro <dac at trilug.org> wrote:
> > 
> > Last I checked it doesn't, each member partition of a RAID5 system needs
> > to be the same size.  So you would have to loose 1.5GB on each disk
> > after sdb based on your layout.
>  
> I disagree with you here, if you are doing RAID5 in HW (really the
> only place to do it).  You use all the disks to make 1 large Raid 5
> Disk that is usually equal to disk size x4 and you partition that. 
> Therefore the OS only sees an sda.  I have that with a system that is
> sda - sde.  Each drive is a Raid5 device and the OS sees it as a drive

Actually I think that is in agreement with what I had said (though I
didn't mention hardware raid, which of course is the better choice if
you have it).  I'm assuming that all your HDs in your hardware raid
setup are of the same size?  That would be the same as making all the
software raid partitions the same size (in software raid, instead of
seeing a new 4/5 sda device you see a new 4/5 mda device, but the same
basic thing).  So it acts the same as your example just replacing
/dev/sda with /dev/mda.

>  Example:
> 
> [lavigne at avtestsvr lavigne]$ df -h
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/sda1             1.4G  415M  986M  30% /
> /dev/sda2              43G   38G  3.6G  92% /home
> /dev/sda3             6.2G  2.0G  3.9G  34% /usr
> /dev/sda5             5.8G   53M  5.4G   1% /tmp
> /dev/sda6             3.4G  334M  2.8G  11% /var
> /dev/sda7             2.9G  195M  2.5G   7% /opt
> /dev/sdb1              67G   64G     0 100% /ISOs
> /dev/sdc1             133G   73G   54G  58% /storage
> /dev/sdc2             133G   72G   54G  57% /mnt/sdc2
> /dev/sdd1             133G   51G   75G  41% /builddrive
> /dev/sdd2             133G   95G   31G  75% /mnt/sdd2
> /dev/sde1             367G  130G  218G  38% /images
> [lavigne at avtestsvr lavigne]$
> 
> 
> > In my world it's always nice to run the OS on RAID5 if you have the
> > option.  Remember that it's not just the down time to reinstall the OS.
> > On RAID5 the system isn't going to stop running when a disk fails (it
> > will slow down).  You can even put the /boot on the raid, and with some
> > carefull grub in MBR setup you can even make sure that your system
> > always reboots even with a failed disk.  Of course this is all about
> > making the system hard to knock down.
> 
> I agree completely here.  The setup above has been up an running for
> over 18 months with a total of 9 disk failures in that time (great
> thing about developmental hard disks) and I have never lost the OS or
> data. (Knock on wood).
> 
> Matthew
-- 
David A. Cafaro
dac(at)cafaro.net
Admin to User: "You did what!?!?!"