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mike160
11-08-2010, 03:19 AM
hi anyone here useing ovh know how to change ovh server raid to 0 i just got a new server from ovh and i am trying to change the raid to 0 becaues am only geting around 874 gb when i could get 2 tb hard drive with changing the raid but dont know how to need help i have tryed theses 2 steps here but they did not work

http://forum.ovh.co.uk/showthread.php?t=1578

http://forum.ovh.co.uk/showthread.php?t=1645

Thelen
11-08-2010, 07:16 AM
I could help, unless you were worried my advice would be biased somehow...

mike160
11-08-2010, 03:00 PM
hi Thelen thanks for the reply yes need your help do you know how to do this set it up to raid 0

Cabalo
11-08-2010, 03:07 PM
Do you have a KVM switch on your server ?

mike160
11-08-2010, 03:58 PM
hi cabalo no i dont i did not think i would ever need it so i did not get it with the server

Cabalo
11-08-2010, 04:00 PM
That would have allowed you to raid0 via hardware, which is my recommended setup.
A soft raid0 on linux is not something I have made yet, so unfortunately for now I can't be of much help.

mike160
11-08-2010, 04:28 PM
np thanks for trying to help me out cabalo but yes thats what i need to do but dont know how to do it a soft raid0

slacker
11-08-2010, 06:05 PM
I assume:
- you have access to OVH manager.
- you don't have hardware raid

You can reinstall the OS from the manager and choose raid0 for the /home partition. / cannot be on raid0, it will stay on raid1.
This is the quickest way, assuming you don't mind a format.

If you don't want to do that, you need to delete the current /home partition and create a new one in raid0 with mdadm.
For example:

mdadm --create /dev/md2 --level=0 --raid-devices=2 /dev/sda2 /dev/sdb2

mike160
11-08-2010, 11:02 PM
ok thanks slacker i will try this

Shinzen
11-09-2010, 06:51 AM
May be you can look in this (http://forum.ovh.co.uk/showthread.php?p=36001) and this (http://ovhservers.com/tag/linux/)

Expeto
11-09-2010, 09:00 PM
mdadm --create /dev/md2 --level=0 --raid-devices=2 /dev/sda2 /dev/sdb2

Slackers, they surely know their way with cli :)

@mike160

My advice will be clean install. You already tried few random advices and failed, its possible that you have already broken something, which might lead to future problems.
At least check `cat /proc/mdstat` to see the current md state of your server before using mdadm.

mike160
11-10-2010, 07:49 AM
thanks all everthing is working now

The_Wire
11-10-2010, 09:51 AM
I'm in the verge of doing the same as mike did, but i would like to ask a few things if i may.
Since we are talking about softraid are there any downsides to having a soft one instead of a hardware raid?
Apart from having 2 separate disks show as one, do you also get a better speed and better allocation and hashing on torrents when you have a softraid?
And am i right to assume that since it's a software thing, then its performance would greatly depend on the specs of the system (cpu,ram etc etc)?

Right now i can see on my ovh server both my disks (1.5tb each) seperately of course (i can download on both if i want) and i'm trying to figure out if it's worth wiping everything and setting up from the start in order to have a soft raid. would i see any difference in rt/rut?

Thank you all

Thelen
11-10-2010, 12:53 PM
softraid is faster in some cases, slower in others. for a seedbox you won't notice.

if you have a gbit server you will definitely notice a faster speed, and 100mbit will be slightly faster.

Cabalo
11-10-2010, 01:07 PM
I'm in the verge of doing the same as mike did, but i would like to ask a few things if i may.
Since we are talking about softraid are there any downsides to having a soft one instead of a hardware raid?
Apart from having 2 separate disks show as one, do you also get a better speed and better allocation and hashing on torrents when you have a softraid?
And am i right to assume that since it's a software thing, then its performance would greatly depend on the specs of the system (cpu,ram etc etc)?

Right now i can see on my ovh server both my disks (1.5tb each) seperately of course (i can download on both if i want) and i'm trying to figure out if it's worth wiping everything and setting up from the start in order to have a soft raid. would i see any difference in rt/rut?

Thank you all
You might want to format the disks as ext4 and tweak them, adding noatime and writeback flags to your mount options. I've noticed increases in hard disk performance to up to 30% on some cases, especially when the disk is nearly overloading.

The_Wire
11-17-2010, 11:56 AM
You might want to format the disks as ext4 and tweak them, adding noatime and writeback flags to your mount options. I've noticed increases in hard disk performance to up to 30% on some cases, especially when the disk is nearly overloading.

Thank you for this information Cabalo! it's a bit techical for me (that noatime writeback flags etc) but i will keep it in mind and search some more for it once i decide to wipe the system and re-setup it.

also thank you Thelen for your input.

The bottom line is that even with soft-raid i will see a difference and will help the hdd and overall performance. So it's worth the effort.

Cabalo
11-17-2010, 03:56 PM
You don't have to wipe your system to use those flags, even if you are on ext3.
There's this tutorial: http://blog.smartlogicsolutions.com/2009/06/04/mount-options-to-improve-ext4-file-system-performance/

mike160
11-27-2010, 01:37 AM
thanks cabalo