Author Topic: RAID setup  (Read 2057 times)

hobbes487

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RAID setup
« on: September 16, 2007, 01:04:03 am »
So I now have the system up and running, but I am having issues setting up my RAID array.  I have 3 500GB sata drives I want to use.  In the RAID config page I create a RAID array and then it gives me the add drive option.  The strange thing is that in the drive drop down it has the 3 drives, but one is 500GB and the other two say 1000GB.  That was weird but I decided just to add them all to the array anyway.  When I do that and click 'Create RAID Array', the Status column reads 'DEGRADED, REBUILDING'.  Then when I click 'Back' it goes back to the main RAID config page and the Status now reads FAILED.

Any ideas?

Do I need to format the disks at all?  They used to be in a hardware raid setup formatted in NTFS.  I have turned off the hardware raid in my bios and was thinking I would just reformat the drive and build a new array for linuxMCE.

EDIT:  Do I need to use SW RAID or can I use the HW RAID on my mobo?  If I can, how do i set that up in lmce.
« Last Edit: September 16, 2007, 07:11:40 pm by hobbes487 »

1audio

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Re: RAID setup
« Reply #1 on: September 17, 2007, 09:27:54 am »
The hardware raid on your board is software masquerading as hardware. Look up Linux software raid and you will learn a lot.Which RAID? 0,1 or 5?
I can't offer help on the specific setup as I have not tried it yet. I have not set up a raid on LMCE yet. I played with it but wasn't free to dive in.

hobbes487

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Re: RAID setup
« Reply #2 on: September 17, 2007, 06:28:46 pm »
Ok, so I should probably turn off the "hardware" RAID in my BIOS settings and just do software RAID.  I have tried this, but it still fails when I try to set up an array in the lmce RAID admin page.

I want to do RAID 5 with my 3 500GB disks.

Has anyone tried to set up a raid array in lmce yet?
« Last Edit: September 17, 2007, 06:30:41 pm by hobbes487 »

1audio

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Re: RAID setup
« Reply #3 on: September 17, 2007, 06:39:24 pm »
I'm not sure you will get much with a RAID 5 with three disks. The data will be 2/3 of the total available data. I know it was tested but I don't know how or how thoroughly.

hobbes487

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Re: RAID setup
« Reply #4 on: September 17, 2007, 07:17:17 pm »
I know I will only get 2/3 capicity with 3 disks, but I plan on adding more in the future.  3 disks is just the minimum.  I'm going to lose at least one disk's capacity if I want any kind of array with redundancy.  I have 6 SATA connections for my array, so it will eventually have 6 disks with 5/6 capacity.  With a total of 2.5TB

hobbes487

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Re: RAID setup
« Reply #5 on: September 18, 2007, 08:08:05 pm »
Has anyone tried to set up a raid array on their core to store media?  Any help would be much appreciated.

goku

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Re: RAID setup
« Reply #6 on: September 19, 2007, 07:03:43 pm »
Has anyone tried to set up a raid array on their core to store media?  Any help would be much appreciated.

I tryed it but ran into problems. when you get that DEGRADED, REBUILDING it means it building the spare that will take over for the raid if one of your disk fails. that process will take a long time on avg if you have larg disks. i didn't try a hradware raid. i was doing the software raid that comes with linux mce. it works but for me it wouldn't keep the raid in ok status. i keep getting degraded or failed and at times it would just remove my hard drives. it was driving me nutz. i tryed bypassing the web gui and making the raid on the console but was having no luck. so to do a raid 5 on linux mce i installed zfs and things are good. zfs is way.... better then the raid tool that comes with linux mce to me. my hardware was tested on gentoo for about a year so it was stable before moving to linux mce.

colinjones

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Re: RAID setup
« Reply #7 on: September 19, 2007, 10:52:12 pm »
For the 2 x 1000GB drives, is it possible that the RAID software is assuming a RAID 0 (span) set and so describing both disks as part of that array? RAID 0 would certainly give you 1000GB, and it may just be a "brain dead" GUI issue in the way it describes this to the user. Perhaps it is just offering you that as a default config and you are expected to override this with a RAID 5 config if you want that across 3 disks. As for the degraded/rebuilding state goku is right - this is normal when you first set up a RAID array and even in hardware RAID will often take several hours for large disks - it is just building the stripes and setting up the parity blocks. Perhaps backing up in the GUI is confusing matters. Can you just confirm the config and then periodically monitor the status over several hours? Or does that come up as "failed" as well?

If you have a "hardware" RAID option it would be worthwhile checking with the hardware/BIOS manufacturer whether this works under Linux. You need to know if it is a system driver running under an OS or whether it runs at a lower level. One way of determining this could be to find out whether it supports providing RAID for the boot system disk (any OS) - if it does then this would imply that it isn't a system driver but implemented at a lower level, in which case it doesn't matter whether it is a real RAID controller or just software masquerading, you should be able to set up a "hardware" RAID container in the BIOS, and this will simply present to Linux as an ordinary (1TB) LUN - Linux should not be capable of distinguishing between it and a normal drive which will make things easier for you and you won't have to work out what is wrong with the Linux software RAID system. Its also safer as you are not dependant on Linux to manage the RAID set, and probably faster, too.

BTW - I assume that you want RAID 5 for redundancy rather than speed? If you are more looking for speed then RAID 5 is not the right choice as this is slower than simple single disks in most operations.
« Last Edit: September 19, 2007, 10:54:00 pm by colinjones »

hobbes487

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Re: RAID setup [SOLVED]
« Reply #8 on: September 21, 2007, 06:09:23 am »
SOLVED!  I figured out the reason why the pluto raid wasn't working was because I hadn't partitioned and formatted the hard drives yet.  I did this with fdisk and now it works like a charm.

Thanks for everyone's help.

cdenning

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Re: RAID setup
« Reply #9 on: October 08, 2007, 06:23:19 am »
Has anyone figured out a work-around for Raid5 with a Live CD install - AMD 64bit (Nvidia NForce Professional 3600/3050)?  I have blown away 4 Vista installs before I determined what the issue was.

1audio

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Re: RAID setup
« Reply #10 on: October 08, 2007, 06:54:26 am »
I'm not clear what you are asking. First I'm not sure what level of support under Ubuntu there is for the chipset. You can add the drivers manually if nVidia has them available. Then lMCE doesn't support 64 bit OS. You need 32 bit version. Finally once that is sorted you need to see if the chipset is supported in the raid driver.

This is why its easier to start with known hardware. You have a very serious server motherboard but its all unknown territory for us.

Please add details so I may be able to help.