Install on Soft Raid

Kyeto

New Member
Nov 27, 2008
3
0
1
Hello,

I know that's the function is disable in proxmox.

But i really need to activate this option.

What i need to modify in proxmox (kernel ?) to boot on raid ?

Thanks
 

tom

Proxmox Staff Member
Staff member
Aug 29, 2006
14,490
584
133
No idea ? :(
Software raid is not supported and makes no sense on Proxmox VE - I assume thats the reason why you get no answers here.
 

thefool808

Member
Jun 24, 2008
59
1
6
Massachusettes
Even though you're thinking to yourself "I need this"... you really actually need to NOT use it. It's not that it's a feature that just isn't available, it's actually a feature that is specifically disabled because it's a bad idea. Just buy a hardware RAID card and you'll be much better off.
 

Kyeto

New Member
Nov 27, 2008
3
0
1
I don't understand why it's a bad idea.
I know how manage a soft raid with mdadm ...

I just want to know how enable it.
How OVH setup proxmox in RAID on their dedicated server.

If not, what is the type of filesystem i need to use on my /var/lib/vz if i put just this partition on my raid
 

dietmar

Proxmox Staff Member
Staff member
Apr 28, 2005
16,704
373
103
Austria
www.proxmox.com
I don't understand why it's a bad idea.
I know how manage a soft raid with mdadm ...
search the forum, there are many reasons (for us)

I just want to know how enable it.
How OVH setup proxmox in RAID on their dedicated server.
I guess thats a question for OVH support.

If not, what is the type of filesystem i need to use on my /var/lib/vz if i put just this partition on my raid
ext3 on top of LVM2 (else you cant create snapshots).

- Dietmar
 

liane

Member
Nov 25, 2008
36
1
8
search the forum, there are many reasons (for us)
Well, that's harsh, at least.

For *us* (read people that have no choice of the hardware, let's say the majority that rent dedicated servers with *no* hardware RAID), that makes just 2 good reasons for not using proxmox:

1) need to install from a physical CD-ROM (not generally available on a rented dedicated server)

2) no soft RAID, so unusable for production.

Those 2 reasons might turn away lots of people from using proxmox.

Perhaps you could offer 2 distributions:

- one officially supported, install from CD, no soft RAID support (the one you actually offer, that works right out of the box, as advertised)

- one *not* supported, over a recommended disk partition, supporting previous RAID+LVM setup, and using no physical CD.

that way, the only reason for not supporting soft RAID (well, the main one I found searching the forums: "because it is too difficult to recover from it" ???) wouldn't be on your hands, because it would not be an officially supported option, but I guess a lot of people (in fact, much more than right now) would still happily use your product.
 

tom

Proxmox Staff Member
Staff member
Aug 29, 2006
14,490
584
133
Well, that's harsh, at least.

For *us* (read people that have no choice of the hardware, let's say the majority that rent dedicated servers with *no* hardware RAID), that makes just 2 good reasons for not using proxmox:

1) need to install from a physical CD-ROM (not generally available on a rented dedicated server)
your hosting provider can install it for you - this is already done by some hosting companies and quite a lot are thinking about this - just contact your hosting companies to offer preinstalled Proxmox VE!

2) no soft RAID, so unusable for production.

Those 2 reasons might turn away lots of people from using proxmox.
For production only hardware raid is possible. if you use an custom softraid you will run now and in future versions into problems means it will NOT work. It´s quite interesting that people does not believe us that Proxmox VE will not work with soft raid - again: we are the developers and we should know it!?

Perhaps you could offer 2 distributions:

- one officially supported, install from CD, no soft RAID support (the one you actually offer, that works right out of the box, as advertised)

- one *not* supported, over a recommended disk partition, supporting previous RAID+LVM setup, and using no physical CD.
We go this way as we think this is the best way. We know softraid is not working in our combination so why should we go for a non working stuff?

that way, the only reason for not supporting soft RAID (well, the main one I found searching the forums: "because it is too difficult to recover from it" ???) wouldn't be on your hands, because it would not be an officially supported option, but I guess a lot of people (in fact, much more than right now) would still happily use your product.
but anyway, you can grab the source code and build an installer with softraid support, but you will see that some functions will not work.
 

grin

Active Member
Dec 8, 2008
108
2
38
Hungary
grin.hu
Dietmar:
I have tried to search the forum for the reasons behind not supporting software raid, but found nothing relevant (beyond repeating that it's not good, hw raid is good, repeat from beginning). Would you be so kind as to at least provide the search keywords you mean?

By the way using software raid is as easy as enabling the given option in the kernel (use the source .config from the sources, see wiki for url), recompiling and done.
 

tom

Proxmox Staff Member
Staff member
Aug 29, 2006
14,490
584
133
Dietmar:
I have tried to search the forum for the reasons behind not supporting software raid, but found nothing relevant (beyond repeating that it's not good, hw raid is good, repeat from beginning). Would you be so kind as to at least provide the search keywords you mean?

By the way using software raid is as easy as enabling the given option in the kernel (use the source .config from the sources, see wiki for url), recompiling and done.
we do not support software raid as its will create problems in our special setup. and we will stop discussing this as we explained it in detail several times.

so for all: please do not ask again and again why we do not use soft raid.
 

grin

Active Member
Dec 8, 2008
108
2
38
Hungary
grin.hu
Tom, no thanks for not answering. I know end users are annoying but you don't have to voice your anger. Ignore them. Us.

Dietmar, thanks for the useful link, I'll include on my personal faq in the wiki, and maybe someday you include in your official faq. (For your kindness a suggestion: upgrade openvz kernel if you haven't done so, there was an ugly memory corruption error before ovz006.2, in some circumstances it crashes the machine daily.)

Others, I'll try to put up a softraid kernel nowadays, just too busy to do it right now.
 

martin

Proxmox Staff Member
Staff member
Apr 28, 2005
663
513
113
(For your kindness a suggestion: upgrade openvz kernel if you haven't done so, there was an ugly memory corruption error before ovz006.2, in some circumstances it crashes the machine daily.)
Proxmox VE uses already ovz006.5
 

xenfasa

New Member
Jan 6, 2009
4
0
1
Hi Grin,

I understand proxmox views on software raid, but my dedicated servers are in another country and I don't trust anyone to open them up to attempt to install HW RAID controllers if such an upgrade would even work without major hassles not to mention costs. So meanwhile, I don't have much choice either.

Others, I'll try to put up a softraid kernel nowadays, just too busy to do it right now.
So Grin, Let me know if you ever get around to having a solution for software RAID I'll be trying some ideas as well. I run several dedicated machines with software RAID and it has always worked for us. Software RAID is better than no RAID and has save me several times. I have had issues with HW RAID Drivers... so another thing I like about software RAID is that it is consistent and flexible no matter what linux you're using you have the same familiar commands at hand and can RAID1 on the fly if you have too.

Thanks,
Xen
 

casey

New Member
Aug 19, 2008
3
0
1
software raid1 seems to work ok

I have a testing box that didn't have a hardware raid card in it so I decided to see if I could get this going for grins. I'm fairly certain this whole setup would break at the least desirable moment and I certainly won't be using this for any production boxes, but it was an interesting diversion into the world of software raid which I'd never used before. The basic order I followed is:

Install Proxmox as usual onto 1 drive(/dev/sda)
aptitude install mdadm initramfs-tools

Edit the modules list for initramfs-tools to force add the raid1 module

mkinitramfs -o /boot/test -r /dev/mapper/pve-root
add a grub list entry to point to my new initrd image

fdisk the 2nd disk to look exactly like the first disk
mdadm --create /dev/md0 --level=1 --raid-devices=2 missing /dev/sdb1
mdadm --create /dev/md1 --level=1 --raid-devices=2 missing /dev/sdb2
mdadm --detail --scan >> /etc/mdadm/mdadm.conf

pvcreate /dev/md1
vgextend pve /dev/md1
pvmove /dev/sda2 /dev/md1
vgreduce pve /dev/sda2

mdadm --add /dev/md1 /dev/sda2
watch -n 1 "cat /proc/mdstat"

mkfs.ext3 /dev/md0
mkdir /mnt/md0
mount /dev/md0 /mnt/md0
cp -ax /boot /mnt/md0

edit fstab to map the /boot to /dev/md0

sfdisk --change-id /dev/sda1 fd
mdadm --add /dev/md0 /dev/sda1

use grub to install bootloader onto the 2nd hard drive
 

Misogynist

New Member
Jan 16, 2009
5
0
1
Just wanted to thank you casey.
I followed your instructions, and now it works like a charm!

Even if it's unsupported - by now I couldn't find a single problem with that configuration..
 

user100

Member
Sep 15, 2008
35
0
6
Helped me too.

I had some problems while creating the partitions the same way on the second harddrive (because the last cylinder of the first partition overlapped with the first cylinder of the second partition - don´t know why) but 'sfdisk -d /dev/sda | sfdisk /dev/sdb --force' did it (and after creation of raid1 was finished i decided to remove again the first partitions and recreate myself manually without that overlapping stuff for ...mhhh "cosmetic reasons"). :D

Copying 'cp -ax /boot /mnt/md0' put me an unwanted "/boot" directory on /mnt/md0 (which would be a /boot/boot when mounted and grub was not happy) but that was just a minor negligibility.

So, thank you casey! :)

Greetings,
user100
 

vegbox

New Member
Dec 4, 2008
6
0
1
Can you have a proxmox system like this

1 Sata = OS Drive

Software Raid Drives = Drive for VEs?

Thanks,
 

drdebian

New Member
Feb 17, 2009
1
0
1
Even though you're thinking to yourself "I need this"... you really actually need to NOT use it. It's not that it's a feature that just isn't available, it's actually a feature that is specifically disabled because it's a bad idea. Just buy a hardware RAID card and you'll be much better off.
I have to disagree about it being a bad idea. For small installations on a budget, SoftwareRAID is a very acceptable solution and not a bad idea at all.

Anyway, I'm also wondering how I would be notified about a defective disk in the array if I were to use a HardwareRAID card. Usually additional software supplied by the vendor has to be installed for this. How is this usually done using ProxmoxVE?
 

tom

Proxmox Staff Member
Staff member
Aug 29, 2006
14,490
584
133
I have to disagree about it being a bad idea. For small installations on a budget, SoftwareRAID is a very acceptable solution and not a bad idea at all.

Anyway, I'm also wondering how I would be notified about a defective disk in the array if I were to use a HardwareRAID card. Usually additional software supplied by the vendor has to be installed for this. How is this usually done using ProxmoxVE?
yes, you should install the raid controller management software. make sure this is available for Debian 64 bit. Adaptec ASM is known to work.
 

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