[linux-lvm] LVM and RAID

[linux-lvm] LVM and RAID

[Tobias Gablunsky]

Hi all!

I didn't find clear information about how to use LVM on an (Software)
RAID-Mirror (or RAID-5). All I found, were problems: LVM uses Partition Type
0x8E but Linux Soft-RAID uses 0xFD - this dosn't look very compatible... A
solution would be to use Hardware-RAID of course. But I'm wondering if there
is a way to use Software-RAID and LVM together - I cannot believe that I am
the first one with this question! Am I?


tobias

Re: [linux-lvm] LVM and RAID

[Mike Williams]

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On Tuesday 04 November 2003 11:49, Tobias Gablunsky wrote:
> Hi all!
> 
> I didn't find clear information about how to use LVM on an (Software)
> RAID-Mirror (or RAID-5). All I found, were problems: LVM uses Partition
> Type\r 0x8E but Linux Soft-RAID uses 0xFD - this dosn't look very
> compatible... A solution would be to use Hardware-RAID of course. But I'm
> wondering if there is a way to use Software-RAID and LVM together - I
> cannot believe that I am the first one with this question! Am I?

I just created the software raid, and pointed pvcreate at it.
Works like a charm.

- -- 
Mike Williams
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RE: [linux-lvm] LVM and RAID

[Tobias Gablunsky]

> 
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> On Tuesday 04 November 2003 11:49, Tobias Gablunsky wrote:
> > Hi all!
> > 
> > I didn't find clear information about how to use LVM on an 
> (Software)
> > RAID-Mirror (or RAID-5). All I found, were problems: LVM 
> uses Partition
> > Type
>  0x8E but Linux Soft-RAID uses 0xFD - this dosn't look very
> > compatible... A solution would be to use Hardware-RAID of 
> course. But I'm
> > wondering if there is a way to use Software-RAID and LVM 
> together - I
> > cannot believe that I am the first one with this question! Am I?
> 
> I just created the software raid, and pointed pvcreate at it.
> Works like a charm.

Well thats fine but if you want your kernel to boot use your RAID-Volumes
automatically you have to give it partition type 0xFD. And if you want
automatically mounted LVM you need to give it the partition type 0x8E - So
did you ever reboot your system?


> 
> - -- 
> Mike Williams
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> iD8DBQE/p5YSInuLMrk7bIwRAk+dAJ42yw0wUImTk3N5dqOfqDa/63ay/gCfWxl5
> vgvk4alAJdy68DRVD2U/cGg=
> =kGxr
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> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 

RE: [linux-lvm] LVM and RAID

[Geoff Dolman]

On Tue, 2003-11-04 at 13:09, Tobias Gablunsky wrote:
> > 
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> > 
> > On Tuesday 04 November 2003 11:49, Tobias Gablunsky wrote:
> > > Hi all!
> > > 
> > > I didn't find clear information about how to use LVM on an 
> > (Software)
> > > RAID-Mirror (or RAID-5). All I found, were problems: LVM 
> > uses Partition
> > > Type
> >  0x8E but Linux Soft-RAID uses 0xFD - this dosn't look very
> > > compatible... A solution would be to use Hardware-RAID of 
> > course. But I'm
> > > wondering if there is a way to use Software-RAID and LVM 
> > together - I
> > > cannot believe that I am the first one with this question! Am I?
> > 
> > I just created the software raid, and pointed pvcreate at it.
> > Works like a charm.
> 
> Well thats fine but if you want your kernel to boot use your RAID-Volumes
> automatically you have to give it partition type 0xFD. And if you want
> automatically mounted LVM you need to give it the partition type 0x8E 


But why? Your RAID set will be made on say /dev/hda1 and /dev/hdb1
creating say /dev/md0, but your lvm partition will exist on /dev/md0.

-- 
Geoff Dolman
JDRF/WT Diabetes and Inflammation Laboratory
Cambridge Institute for Medical Research
University of Cambridge
http://www-gene.cimr.cam.ac.uk/todd/

[linux-lvm] LVM and RAID

[Tobias Gablunsky]

Hi all!

I didn't find clear information about how to use LVM on an (Software)
RAID-Mirror (or RAID-5). All I found, were problems: LVM uses Partition Type
0x8E but Linux Soft-RAID uses 0xFD - this dosn't look very compatible... A
solution would be to use Hardware-RAID of course. But I'm wondering if there
is a way to use Software-RAID and LVM together - I cannot believe that I am
the first one with this question! Am I?


tobias gablunsky
systemtechnik internet

CBXNET combox internet service gmbh
potsdamer strasse 96 | 10785 berlin
tel: +49 (30) 5 900 6 900 
fax: +49 (30) 5 900 6 999 
www.cbxnet.de | support@cbxnet.de

Re: [linux-lvm] LVM and RAID

[Goetz Bock]

On Tue, Nov 04 '03 at 12:49, Tobias Gablunsky wrote:
> I didn't find clear information about how to use LVM on an (Software)
> RAID-Mirror (or RAID-5). All I found, were problems: LVM uses Partition Type
> 0x8E but Linux Soft-RAID uses 0xFD - this dosn't look very compatible...
Well, it just works. You make an autodetection softRAID (e.g. partition
type 0xFD) and make that a PV.

No need to have partition type 0x8e. LVM does not care about the
partition type, and you don't even have a partition type on softRAID.
-- 
/"\ Goetz Bock at blacknet dot de  --  secure mobile Linux everNETting
\ /                     (c) 2003 as GNU FDL 1.1
 X   [ 1. Use descriptive subjects - 2. Edit a reply for brevity -  ]
/ \  [ 3. Reply to the list - 4. Read the archive *before* you post ]

Re: [linux-lvm] LVM and RAID

[Martin Mosny]

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hi all,

> I didn't find clear information about how to use LVM on an (Software)
> RAID-Mirror (or RAID-5). All I found, were problems: LVM uses Partition Type
> 0x8E but Linux Soft-RAID uses 0xFD - this dosn't look very compatible... A
> solution would be to use Hardware-RAID of course. But I'm wondering if there
> is a way to use Software-RAID and LVM together - I cannot believe that I am
> the first one with this question! Am I?

As Goetz Bock say - just use 0xFD for raid

   Device Boot    Start       End    Blocks   Id  System
/dev/hda3           138      9729  77047740   fd  Linux raid autodetect

make all the raid stuff:

raiddev             /dev/md1
raid-level                  1
nr-raid-disks               2
chunk-size                  64k
persistent-superblock       1
nr-spare-disks              0
    device          /dev/hda3
    raid-disk     0
    device          /dev/hdb3
    raid-disk     1

after them make all the lvm stuff

- --
Best regards
     Martin Mosny

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Re: [linux-lvm] LVM and RAID

[Toad]

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On Tue, Nov 04, 2003 at 01:21:51PM +0000, Geoff Dolman wrote:
> On Tue, 2003-11-04 at 13:09, Tobias Gablunsky wrote:
> > > 
> > > -----BEGIN PGP SIGNED MESSAGE-----
> > > Hash: SHA1
> > > 
> > > On Tuesday 04 November 2003 11:49, Tobias Gablunsky wrote:
> > > > Hi all!
> > > > 
> > > > I didn't find clear information about how to use LVM on an 
> > > (Software)
> > > > RAID-Mirror (or RAID-5). All I found, were problems: LVM 
> > > uses Partition
> > > > Type
> > >  0x8E but Linux Soft-RAID uses 0xFD - this dosn't look very
> > > > compatible... A solution would be to use Hardware-RAID of 
> > > course. But I'm
> > > > wondering if there is a way to use Software-RAID and LVM 
> > > together - I
> > > > cannot believe that I am the first one with this question! Am I?
> > > 
> > > I just created the software raid, and pointed pvcreate at it.
> > > Works like a charm.
> > 
> > Well thats fine but if you want your kernel to boot use your RAID-Volumes
> > automatically you have to give it partition type 0xFD. And if you want
> > automatically mounted LVM you need to give it the partition type 0x8E 
> 
> 
> But why? Your RAID set will be made on say /dev/hda1 and /dev/hdb1
> creating say /dev/md0, but your lvm partition will exist on /dev/md0.

Does the kernel autodetection work in this case? Would you need to
partition /dev/md0 into a boot partition and an LVM PV?
> 
> -- 
> Geoff Dolman
> JDRF/WT Diabetes and Inflammation Laboratory
> Cambridge Institute for Medical Research
> University of Cambridge
> http://www-gene.cimr.cam.ac.uk/todd/
> 
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

-- 
Matthew J Toseland - toad@amphibian.dyndns.org
Freenet Project Official Codemonkey - http://freenetproject.org/
ICTHUS - Nothing is impossible. Our Boss says so.

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Re: [linux-lvm] LVM and RAID

[Holger Parplies]

Toad wrote:
> On Tue, Nov 04, 2003 at 01:21:51PM +0000, Geoff Dolman wrote:
> > On Tue, 2003-11-04 at 13:09, Tobias Gablunsky wrote:
> > > [...]
> > > Well thats fine but if you want your kernel to boot use your RAID-Volumes
> > > automatically you have to give it partition type 0xFD. And if you want
> > > automatically mounted LVM you need to give it the partition type 0x8E 
> > 
> > But why? Your RAID set will be made on say /dev/hda1 and /dev/hdb1
> > creating say /dev/md0, but your lvm partition will exist on /dev/md0.
> 
> Does the kernel autodetection work in this case?

Yes. Presuming your init scripts start RAID first before executing
vgscan ...

Why should it not work? vgscan doesn't care about partition types. It
scans possible block devices for LVM metadata (in LVM1 it's a hardcoded
list of devices, in LVM2 it's configurable, I believe). Among these are
the raid devices, so if they're active, they'll be recognized as PVs.

> Would you need to partition /dev/md0 into a boot partition and an LVM PV?

No. You can't anyway, as far as I'm aware. Well, you can probably write
a partition table to it, but you can do that with /dev/zero too (I just
tried it out :-). Nobody will use it.

Regards,

Holger

[linux-lvm] LVM and RAID

[Thomas Bellembois]

Hello,

I wonder if we can use RAID (hard) under LVM for Xen domU.
What kind of RAID is recommanded ?

I was thinking about the following configuration:
- RAID 1 (two 70 GB disks) for the dom0
- RAID 5 (three 285 GB disks) for domU on LVM partitions

Any idea ?

Regards,

Thomas

RE: [linux-lvm] LVM and RAID

[Gerrard Geldenhuis]

Hi Thomas,
You most certainly can, however I believe your question to be more
relevant to a xen mailing list. Might I suggest fedora-xen@redhat.com. I
don't have the subscribing page to hand right now...

Regards

> -----Original Message-----
> From: linux-lvm-bounces@redhat.com
[mailto:linux-lvm-bounces@redhat.com]
> On Behalf Of Thomas Bellembois
> Sent: 08 February 2008 10:55
> To: linux-lvm@redhat.com
> Subject: [linux-lvm] LVM and RAID
> 
> Hello,
> 
> I wonder if we can use RAID (hard) under LVM for Xen domU.
> What kind of RAID is recommanded ?
> 
> I was thinking about the following configuration:
> - RAID 1 (two 70 GB disks) for the dom0
> - RAID 5 (three 285 GB disks) for domU on LVM partitions
> 
> Any idea ?
> 
> Regards,
> 
> Thomas
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/