Install / as RAID 0

[Richard Shaw]

I got some very old computers (Pentium 4) and quite frankly it's choking on
the installer (40 minutes to draw a window to setup partitions), but since
it's a system I don't care about I wanted to experiment with RAID since
I've never done so before.

To make setting up the partitions easier I used System Rescue CD which
boots up and is usable within a reasonable amount of time. The systems came
with 80GB drives so I move one over and setup the partition layout is as
follows:

/dev/sda1 /boot 4GB (too big, but I want it to match partition 1 on sdb)
/dev/sda2 RAID 0 (remainder)
/dev/sdb1 SWAP 4GB
/dev/sdb2 RAID 0 (remainder)

I setup the RAID 0 with mdadm... I still don't know exactly what I'm doing
but I ended up using the LXDE spin because Gnome Live was unusable.
Sometimes the installer sees /dev/md0 and sometimes it doesn't (shows 0
bytes available).

The one time I got through the partitioning using bivlet it complained
about /dev/sdb1 and wouldn't show OK on the main screen, but that's SWAP,
why does it care? If I don't select both drives it won't let me setup
/dev/md0.

Yesterday I tried installing Bodhi linux, I would rather stay with Fedora
or at least something RPM based but it seemed to run decently and the
installer recognized /dev/md0 (after I did an apt install mdadm which
auto-created /etc/mdadm/mdadm.conf) and let me install to it.

However... One I rebooted it dropped into busybox. I assume this is either
because /etc is on root so it can't see it OR I need to recreate the initrd
with the right kernel module? Not sure and I haven't been able to find good
instructions for root as RAID... Probably not a good idea, but it's a trash
system so I was just playing with it anyway.

Ideas?

Thanks,
Richard

[Doug H.]

On Tue, 2018-10-16 at 08:06 -0500, Richard Shaw wrote:
>  I got some very old computers (Pentium 4) and quite frankly it's
>  choking on the installer (40 minutes to draw a window to setup
>  partitions), but since it's a system I don't care about I wanted to
>  experiment with RAID since I've never done so before.
>  
>  To make setting up the partitions easier I used System Rescue CD
>  which boots up and is usable within a reasonable amount of time. The
>  systems came with 80GB drives so I move one over and setup the
>  partition layout is as follows:
>  
>  /dev/sda1 /boot 4GB (too big, but I want it to match partition 1 on
>  sdb)
>  /dev/sda2 RAID 0 (remainder)
>  /dev/sdb1 SWAP 4GB
>  /dev/sdb2 RAID 0 (remainder)
>  
>  I setup the RAID 0 with mdadm... 
If you just want to get it installed so that you can play with it, then
the installer can do the raid creation for you. I agree that there is
value in learning to do it via mdadm before hand but that is really not
required now.

I used vitual box to do a minimal install using:

Fedora-Workstation-netinst-x86_64-28-1.1.iso

I made all partitions raid0 just to test it.

I used the custom disk setup option and created the below...
(nothing changed after install)

$ df -Th
Filesystem     Type      Size  Used Avail Use% Mounted on
devtmpfs       devtmpfs  483M     0  483M   0% /dev
tmpfs          tmpfs     493M     0  493M   0% /dev/shm
tmpfs          tmpfs     493M  604K  492M   1% /run
tmpfs          tmpfs     493M     0  493M   0% /sys/fs/cgroup
/dev/md125     ext4      6.6G  873M  5.4G  14% /
tmpfs          tmpfs     493M  4.0K  493M   1% /tmp
/dev/md126     ext4      575M   88M  446M  17% /boot
tmpfs          tmpfs      99M     0   99M   0% /run/user/1000

$ swapon -s
Filename		Type		Size	Used	Priority
/dev/md127             	partition	2099196	0	-2


$ cat /proc/mdstat 
Personalities : [raid0] 
md125 : active raid0 sda3[0] sdb3[1]
      7032832 blocks super 1.2 512k chunks
      
md126 : active raid0 sdb2[1] sda2[0]
      614400 blocks super 1.2 512k chunks
      
md127 : active raid0 sda1[0] sdb1[1]
      2099200 blocks super 1.2 512k chunks
      
unused devices: <none>



$ ls -la /dev/md
total 0
drwxr-xr-x.  2 root root  100 Oct 16 07:33 .
drwxr-xr-x. 20 root root 3860 Oct 16 07:33 ..
lrwxrwxrwx.  1 root root    8 Oct 16 07:33 boot -> ../md126
lrwxrwxrwx.  1 root root    8 Oct 16 07:33 root -> ../md125
lrwxrwxrwx.  1 root root    8 Oct 16 07:33 swap -> ../md127


-- 
Doug H.

[Richard Shaw]

On Tue, Oct 16, 2018 at 9:38 AM Doug H. <fedoraproject.org(a)wombatz.com&gt;
wrote:

>  If you just want to get it installed so that you can play with it, then
>  the installer can do the raid creation for you. I agree that there is
>  value in learning to do it via mdadm before hand but that is really not
>  required now.
>  
>  I used vitual box to do a minimal install using:
>
>  Fedora-Workstation-netinst-x86_64-28-1.1.iso
>
>  I made all partitions raid0 just to test it.
>
>  I used the custom disk setup option and created the below...
>  (nothing changed after install)
>  
Ok, so just to confirm, you do have to choose the bivlet-gui method of
partitioning to setup RAID, correct?

Thanks,
Richard

[Doug H.]

On Tue, 2018-10-16 at 09:53 -0500, Richard Shaw wrote:
>  On Tue, Oct 16, 2018 at 9:38 AM Doug H. <
>  fedoraproject.org(a)wombatz.com&gt; wrote:
>  > If you just want to get it installed so that you can play with it,
>  > then
>  > the installer can do the raid creation for you. I agree that there
>  > is
>  > value in learning to do it via mdadm before hand but that is really
>  > not
>  > required now.
>  > I used vitual box to do a minimal install using:
>  > 
>  > Fedora-Workstation-netinst-x86_64-28-1.1.iso
>  > 
>  > I made all partitions raid0 just to test it.
>  > 
>  > I used the custom disk setup option and created the below...
>  > (nothing changed after install)
>  
>  Ok, so just to confirm, you do have to choose the bivlet-gui method
>  of partitioning to setup RAID, correct? 
Sorry, should have said. I did *not* use that mode since I have recent
experience using the regular "custom" option. I had recently done the
same test using raid1 so I was curious if 0 would also be allowed for
all partitions. I can't even remember if I have checked out the bivlet
thing yet so will give it a spin to see what it looks like.

For the regular/custom it is just a simple pull down that selects raid 
levels among other options.

-- 
Doug H.

[Doug H.]

On Tue, 2018-10-16 at 09:53 -0500, Richard Shaw wrote:
>  On Tue, Oct 16, 2018 at 9:38 AM Doug H. <
>  fedoraproject.org(a)wombatz.com&gt; wrote:
>  > If you just want to get it installed so that you can play with it,
>  > then
>  > the installer can do the raid creation for you. I agree that there
>  > is
>  > value in learning to do it via mdadm before hand but that is really
>  > not
>  > required now.
>  > I used vitual box to do a minimal install using:
>  > 
>  > Fedora-Workstation-netinst-x86_64-28-1.1.iso
>  > 
>  > I made all partitions raid0 just to test it.
>  > 
>  > I used the custom disk setup option and created the below...
>  > (nothing changed after install)
>  
>  Ok, so just to confirm, you do have to choose the bivlet-gui method
>  of partitioning to setup RAID, correct? 

I have not done the actual install yet but I just did the setup using
the bivlet thing. It was just a bit more "expert" but not much. It
looks like it would be happy to build a degraded raid with just one
device. Not sure if the base level "custom" would allow that.

Otherwise it does look like this would work fine and it does seem to
give you some more options. But personally I would suggest you just use
the regular "custom" build to get it going since you are new to playing
with raid.

P.S. One thing I was surprised about is that the raids from my first
test were not created with bitmaps. Maybe that is not as helpful for
raid0. My experience is with raid1.

-- 
Doug H.

[Doug H.]

On Tue, 2018-10-16 at 09:53 -0500, Richard Shaw wrote:
>  On Tue, Oct 16, 2018 at 9:38 AM Doug H. <
>  fedoraproject.org(a)wombatz.com&gt; wrote:
>  > If you just want to get it installed so that you can play with it,
>  > then
>  > the installer can do the raid creation for you. I agree that there
>  > is
>  > value in learning to do it via mdadm before hand but that is really
>  > not
>  > required now.
>  > I used vitual box to do a minimal install using:
>  > 
>  > Fedora-Workstation-netinst-x86_64-28-1.1.iso
>  > 
>  > I made all partitions raid0 just to test it.
>  > 
>  > I used the custom disk setup option and created the below...
>  > (nothing changed after install)
>  
>  Ok, so just to confirm, you do have to choose the bivlet-gui method
>  of partitioning to setup RAID, correct? 

Before deleting the tests I happened to notice that my first "custom"
install did not actually use the full available space on the two drives
for the root partition. This seems to be due to selecting the size
before setting it to raid0. The installer had topped out the size
before I was able to tell it that it gets both drive partitions to use.
The solution was to select 100G for the size of the "/" partition as a
last step. It then simply set it to the full available space remaining.
So that is a small "got ya" issue for the "Custom" option that the
bivlet does not seem to suffer from.


-- 
Doug H.

[Richard Shaw]

On Tue, Oct 16, 2018 at 10:58 AM Doug H. <fedoraproject.org(a)wombatz.com&gt;
wrote:

>  Before deleting the tests I happened to notice that my first "custom"
>  install did not actually use the full available space on the two drives
>  for the root partition. This seems to be due to selecting the size
>  before setting it to raid0. The installer had topped out the size
>  before I was able to tell it that it gets both drive partitions to use.
>  The solution was to select 100G for the size of the "/" partition as a
>  last step. It then simply set it to the full available space remaining.
>  So that is a small "got ya" issue for the "Custom" option that the
>  bivlet does not seem to suffer from.
>  
Yup, finally got back to playing with it and I'm a little annoyed. Bought
some used memory on ebay to max it out (2GB) and it turns out only 1.5GB is
detected. The memory was described as single sided matched set... Well one
was, one was double sided. This old thing is pretty picky. But I only paid
$6 to my door so...

Got Fedora 28 LXDE installed and setting up the RAID 0 with bivlet was
pretty easy. Since it's more or less a throw away system I went ahead and
did like you, RAID for everything (/boot, swap, remainder "/").

Sounds like a 747 taking off when it has to crunch on something but I/O
access is pretty spiffy.

Thanks for the pointers!

Richard

[Samuel Sieb]

On 10/21/18 5:03 PM, Richard Shaw wrote:
>  Got Fedora 28 LXDE installed and setting up the RAID 0 with bivlet
> was 
>  pretty easy. Since it's more or less a throw away system I went ahead  
I just want to point out that the actual name is "blivet".  And if you 
look up the definition of that word, you might find it somewhat 
appropriate. ;-)

[Richard Shaw]

On Sun, Oct 21, 2018 at 9:36 PM Samuel Sieb <samuel(a)sieb.net&gt; wrote:

>  On 10/21/18 5:03 PM, Richard Shaw wrote:
>  > Got Fedora 28 LXDE installed and setting up the RAID 0 with bivlet was
>  > pretty easy. Since it's more or less a throw away system I went ahead
>
>  I just want to point out that the actual name is "blivet".  And if you
>  look up the definition of that word, you might find it somewhat
>  appropriate. ;-)
>  
Whoops, but it does roll of the tongue easier though...

Thanks,
Richard