LVM Multipathing

LVM Multipathing

[shahid shaikh]

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Hi,

I am trying to test multipathing on lvm2.

Configuration that i am using is as below:

OS                     : SLES9 ( kernel 2.6.5)
lvm                     : lvm2-2.00.15-0.3
multipath-tools    : multipath-tools-0.2.1
udev                   : udev-021-36.32
sysfs                  : sblim-cmpi-sysfs-1.1.5-0.2
hotplug               : hotplug-0.44-32.21 and hotplugctl-0.08-264.1
device-mapper     : device-mapper-1.00.09-17.5

I tried following things :

When I dont have multipaths for LUNs:
1) I tried to create PVs on LUNs using pvcreate
2) Then VGs using above PVs by command vgcreate
3) Then I have created some LVs on VGs.
4) I also fire some I/O on these LVs.
All aboe commands worked succesfully reflecting changes in pvscan, vgscan
and lvscan.

When I have multiplepaths to LUNs:
I tried to create PV on one of the device but on doing pvscan it shows me
some other device.
    e.g  My LUN no 5 has for paths so I can see these four paths as
/dev/sdb, /dev/sdg, /dev/sdl and /dev/sdq.
          then i did following
	   linux# pvcreate /dev/sdb
	   /dev/sdb successfully created
         linux# pvscan
	 	Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdb not
/dev/sdq
		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdg not
/dev/sdq
  		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdl not
/dev/sdq
 		PV /dev/sdq    VG vg01   lvm2 [1.00 GB / 972.00 MB free]
  		Total: 1 [1.00 GB] / in use: 1 [1.00 GB] / in no VG: 0 [0   ]

	  linux# vgcreate vg01
		succesfully created

	  linux# vgscan
 		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdb not
/dev/sdq
		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdg not
/dev/sdq
  		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdl not
/dev/sdq

 I tried the same thing with all permutations but i couldnt create a volume
group.

 I also have  multipath-tools-0.3.9 and  multipath-tools-0.4.2.
 But I am not sure whether they will compatible with kernel 2.6.5.

If you can help me in this scenario I will be thankfull to you.
Please let me know the steps through which I can achieve multipathing on my
configuration.

Thanks and Regards,
Shahid Shaikh.



http://www.patni.com
World-Wide Partnerships. World-Class Solutions.
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Re: LVM Multipathing

[Christophe Varoqui]

Hello,

This is documented in the multipath-tools' FAQ.
In lvm2.conf, you need to exclude the paths from the scaning, and allow 
DM devices to be scaned.

regards,
cvaroqui

shahid shaikh wrote:

>Hi,
>
>I am trying to test multipathing on lvm2.
>
>Configuration that i am using is as below:
>
>OS                     : SLES9 ( kernel 2.6.5)
>lvm                     : lvm2-2.00.15-0.3
>multipath-tools    : multipath-tools-0.2.1
>udev                   : udev-021-36.32
>sysfs                  : sblim-cmpi-sysfs-1.1.5-0.2
>hotplug               : hotplug-0.44-32.21 and hotplugctl-0.08-264.1
>device-mapper     : device-mapper-1.00.09-17.5
>
>I tried following things :
>
>When I dont have multipaths for LUNs:
>1) I tried to create PVs on LUNs using pvcreate
>2) Then VGs using above PVs by command vgcreate
>3) Then I have created some LVs on VGs.
>4) I also fire some I/O on these LVs.
>All aboe commands worked succesfully reflecting changes in pvscan, vgscan
>and lvscan.
>
>When I have multiplepaths to LUNs:
>I tried to create PV on one of the device but on doing pvscan it shows me
>some other device.
>    e.g  My LUN no 5 has for paths so I can see these four paths as
>/dev/sdb, /dev/sdg, /dev/sdl and /dev/sdq.
>          then i did following
>	   linux# pvcreate /dev/sdb
>	   /dev/sdb successfully created
>         linux# pvscan
>	 	Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdb not
>/dev/sdq
>		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdg not
>/dev/sdq
>  		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdl not
>/dev/sdq
> 		PV /dev/sdq    VG vg01   lvm2 [1.00 GB / 972.00 MB free]
>  		Total: 1 [1.00 GB] / in use: 1 [1.00 GB] / in no VG: 0 [0   ]
>
>	  linux# vgcreate vg01
>		succesfully created
>
>	  linux# vgscan
> 		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdb not
>/dev/sdq
>		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdg not
>/dev/sdq
>  		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdl not
>/dev/sdq
>
> I tried the same thing with all permutations but i couldnt create a volume
>group.
>
> I also have  multipath-tools-0.3.9 and  multipath-tools-0.4.2.
> But I am not sure whether they will compatible with kernel 2.6.5.
>
>If you can help me in this scenario I will be thankfull to you.
>Please let me know the steps through which I can achieve multipathing on my
>configuration.
>
>Thanks and Regards,
>Shahid Shaikh.
>
>
>
>http://www.patni.com
>World-Wide Partnerships. World-Class Solutions.
>_____________________________________________________________________
>
>This e-mail message may contain proprietary, confidential or legally
>privileged information for the sole use of the person or entity to
>whom this message was originally addressed. Any review, e-transmission
>dissemination or other use of or taking of any action in reliance upon
>this information by persons or entities other than the intended
>recipient is prohibited. If you have received this e-mail in error
>kindly delete  this e-mail from your records. If it appears that this
>mail has been forwarded to you without proper authority, please notify
>us immediately at netadmin@patni.com and delete this mail. 
>_____________________________________________________________________
>  
>
>------------------------------------------------------------------------
>
>--
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>dm-devel@redhat.com
>https://www.redhat.com/mailman/listinfo/dm-devel
>


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RE: LVM Multipathing

[shahid shaikh]

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Hello,

I seen FAQ. Part relevant to me from FAQ (copied below) consist semething
related to files /etc/mkinitrd/modules and
/etc/mkinitrd/scripts.
But these files are not peresnt at the given location on my system.
I have installed udev-021-36.32 and multipath-tools-0.2.1 ( one which come
bundled with SLES9).
Please let me know why they are not present over. is there something still
missing?
Or i need install something else ( obviously excluding OS)?

	1. How to set up System-on-multipath ?
	======================================

	prerequisite : udev and multipath-tools installed

	here are the steps on a Debian SID system :

	* add dm-mpath and dm-multipath to /etc/mkinitrd/modules
	* copy $tools_dir/multipath/0[12]_* to /etc/mkinitrd/scripts
	* define a friendly alias for your multipathed root disk
	  (in /etc/multipath.conf). Example : "system"
	* enable busybox in /etc/mkinitrd/mkinitrd.conf and set ROOT
	  to any valid block-device (but not a /dev/dm-* one, due to
	  an mkintrd misbelief that all dm-* are managed by LVM2)
	* run mkinitrd
	* in /boot/grub/menu.lst, define the root= kernel parameter
	  Example : root=/dev/system1
	* modify /etc/fstab to reference /dev/system* partitions

	At reboot, you should see some info like :

	path /dev/sda : multipath system
	...
	gpt: 0 slices
	dos: 5 slices
	reduced size of partition #2 to 63
	Added system1 : 0 70685937 linear /dev/system 63
	Added system2 : 0 63 linear /dev/system 7068600
	Added system5 : 0 995967 linear /dev/system 70686063
	...

Thanks and Regards,
Shahid Shaikh.


-----Original Message-----
From: Christophe Varoqui [mailto:christophe.varoqui@free.fr]
Sent: Sunday, February 13, 2005 3:59 PM
To: shahid.shaikh@patni.com; device-mapper development
Subject: Re: [dm-devel] LVM Multipathing


Hello,

This is documented in the multipath-tools' FAQ.
In lvm2.conf, you need to exclude the paths from the scaning, and allow
DM devices to be scaned.

regards,
cvaroqui

shahid shaikh wrote:

>Hi,
>
>I am trying to test multipathing on lvm2.
>
>Configuration that i am using is as below:
>
>OS                     : SLES9 ( kernel 2.6.5)
>lvm                     : lvm2-2.00.15-0.3
>multipath-tools    : multipath-tools-0.2.1
>udev                   : udev-021-36.32
>sysfs                  : sblim-cmpi-sysfs-1.1.5-0.2
>hotplug               : hotplug-0.44-32.21 and hotplugctl-0.08-264.1
>device-mapper     : device-mapper-1.00.09-17.5
>
>I tried following things :
>
>When I dont have multipaths for LUNs:
>1) I tried to create PVs on LUNs using pvcreate
>2) Then VGs using above PVs by command vgcreate
>3) Then I have created some LVs on VGs.
>4) I also fire some I/O on these LVs.
>All aboe commands worked succesfully reflecting changes in pvscan, vgscan
>and lvscan.
>
>When I have multiplepaths to LUNs:
>I tried to create PV on one of the device but on doing pvscan it shows me
>some other device.
>    e.g  My LUN no 5 has for paths so I can see these four paths as
>/dev/sdb, /dev/sdg, /dev/sdl and /dev/sdq.
>          then i did following
>	   linux# pvcreate /dev/sdb
>	   /dev/sdb successfully created
>         linux# pvscan
>	 	Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdb not
>/dev/sdq
>		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdg not
>/dev/sdq
>  		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdl not
>/dev/sdq
> 		PV /dev/sdq    VG vg01   lvm2 [1.00 GB / 972.00 MB free]
>  		Total: 1 [1.00 GB] / in use: 1 [1.00 GB] / in no VG: 0 [0   ]
>
>	  linux# vgcreate vg01
>		succesfully created
>
>	  linux# vgscan
> 		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdb not
>/dev/sdq
>		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdg not
>/dev/sdq
>  		Found duplicate PV owucgI06ZCWQHX6rM3Jyj6UKsr5MOt7E: using /dev/sdl not
>/dev/sdq
>
> I tried the same thing with all permutations but i couldnt create a volume
>group.
>
> I also have  multipath-tools-0.3.9 and  multipath-tools-0.4.2.
> But I am not sure whether they will compatible with kernel 2.6.5.
>
>If you can help me in this scenario I will be thankfull to you.
>Please let me know the steps through which I can achieve multipathing on my
>configuration.
>
>Thanks and Regards,
>Shahid Shaikh.
>
>
>
>http://www.patni.com
>World-Wide Partnerships. World-Class Solutions.
>_____________________________________________________________________
>
>This e-mail message may contain proprietary, confidential or legally
>privileged information for the sole use of the person or entity to
>whom this message was originally addressed. Any review, e-transmission
>dissemination or other use of or taking of any action in reliance upon
>this information by persons or entities other than the intended
>recipient is prohibited. If you have received this e-mail in error
>kindly delete  this e-mail from your records. If it appears that this
>mail has been forwarded to you without proper authority, please notify
>us immediately at netadmin@patni.com and delete this mail.
>_____________________________________________________________________
>
>
>------------------------------------------------------------------------
>
>--
>dm-devel mailing list
>dm-devel@redhat.com
>https://www.redhat.com/mailman/listinfo/dm-devel
>



http://www.patni.com
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privileged information for the sole use of the person or entity to
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recipient is prohibited. If you have received this e-mail in error
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Re: LVM Multipathing

[Christophe Varoqui]

I was thinking about that part :

---


      3. LVM2 doesn't see my multipathed devices as PV, what's up ?

By default, lvm2 does not consider device-mapper block devices (such as 
a dm-crypt device) for use as physical volumes.

In order to use a dm-crypt device as an lvm2 pv, add this line to the 
devices block in /etc/lvm/lvm.conf:

types = [ "device-mapper", 16 ]

If /etc/lvm/lvm.conf does not exist, you can create one based on your 
current/default config like so:

lvm dumpconfig > /etc/lvm/lvm.conf

(tip from Christophe Saout)
---

... then again,

"you need to exclude the paths from the scaning"


regards,
cvaroqui

shahid shaikh wrote:

>Hello,
>
>I seen FAQ. Part relevant to me from FAQ (copied below) consist semething
>related to files /etc/mkinitrd/modules and
>/etc/mkinitrd/scripts.
>But these files are not peresnt at the given location on my system.
>I have installed udev-021-36.32 and multipath-tools-0.2.1 ( one which come
>bundled with SLES9).
>Please let me know why they are not present over. is there something still
>missing?
>Or i need install something else ( obviously excluding OS)?
>  
>


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RE: LVM Multipathing

[shahid shaikh]

[-- Attachment #1: Type: text/plain, Size: 2384 bytes --]

I tried it previously and now also. But it doesnt get me out of trouble.

That's why i tried the 1st FAQ. 
Can you please elaborate what can be wrong in all this stuff?

Thanks and Regards, 
Shahid Shaikh. 

-----Original Message-----
From: Christophe Varoqui [mailto:christophe.varoqui@free.fr]
Sent: Sunday, February 13, 2005 5:23 PM
To: shahid.shaikh@patni.com; device-mapper development
Subject: Re: [dm-devel] LVM Multipathing


I was thinking about that part :

---


      3. LVM2 doesn't see my multipathed devices as PV, what's up ?

By default, lvm2 does not consider device-mapper block devices (such as 
a dm-crypt device) for use as physical volumes.

In order to use a dm-crypt device as an lvm2 pv, add this line to the 
devices block in /etc/lvm/lvm.conf:

types = [ "device-mapper", 16 ]

If /etc/lvm/lvm.conf does not exist, you can create one based on your 
current/default config like so:

lvm dumpconfig > /etc/lvm/lvm.conf

(tip from Christophe Saout)
---

... then again,

"you need to exclude the paths from the scaning"


regards,
cvaroqui

shahid shaikh wrote:

>Hello,
>
>I seen FAQ. Part relevant to me from FAQ (copied below) consist semething
>related to files /etc/mkinitrd/modules and
>/etc/mkinitrd/scripts.
>But these files are not peresnt at the given location on my system.
>I have installed udev-021-36.32 and multipath-tools-0.2.1 ( one which come
>bundled with SLES9).
>Please let me know why they are not present over. is there something still
>missing?
>Or i need install something else ( obviously excluding OS)?
>  
>



http://www.patni.com
World-Wide Partnerships. World-Class Solutions.
_____________________________________________________________________

This e-mail message may contain proprietary, confidential or legally
privileged information for the sole use of the person or entity to
whom this message was originally addressed. Any review, e-transmission
dissemination or other use of or taking of any action in reliance upon
this information by persons or entities other than the intended
recipient is prohibited. If you have received this e-mail in error
kindly delete  this e-mail from your records. If it appears that this
mail has been forwarded to you without proper authority, please notify
us immediately at netadmin@patni.com and delete this mail. 
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LVM Targets

[shahid shaikh]

[-- Attachment #1: Type: text/plain, Size: 1116 bytes --]

Hi christophe,

I was trying to create Error and Mirror kind of targets for DM. But I
couldnt find the appropriate options or parametrs to do the same. I have
tried and succeded in creating Linear, Striped and Snapshot kind of targets.

Please help me out.

Thanks and Regards,
Shahid Shaikh.



http://www.patni.com
World-Wide Partnerships. World-Class Solutions.
_____________________________________________________________________

This e-mail message may contain proprietary, confidential or legally
privileged information for the sole use of the person or entity to
whom this message was originally addressed. Any review, e-transmission
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recipient is prohibited. If you have received this e-mail in error
kindly delete  this e-mail from your records. If it appears that this
mail has been forwarded to you without proper authority, please notify
us immediately at netadmin@patni.com and delete this mail. 
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