[linux-lvm] How do you create large numbers of LVs? (In the 1000s) Is it even possible?

[linux-lvm] How do you create large numbers of LVs? (In the 1000s) Is it even possible?

[Nathaniel Stahl]

We'd like to be able to create a large number of LVs (potentially 
numbering in the low thousands).  I get failure after LV 226 or so, 
though - "VG VolGroup01 metadata writing failed".

RedHat claims this should be possible with LVM2 on the following web page:

http://www.redhat.com/magazine/009jul05/features/lvm2/

I admit to being a little suprised at the 2^32 max LV claim - I was 
figuring 2^20 as the theoretical max given 2.6's 32 bit device numbering 
scheme (20 bits for minor, 12 bits for major).

The LVM2 code, at least version 2.00.25 as distributed in FC3, appears 
to have a check that the minor number is strictly less than 256.  
Removing this check allows for the creation of working LVs using minors 
greater than 256, but LV creation fails with the error "VG VolGroup01 
metadata writing failed" creating the 227th LV.  Even with the minor 
limit in place - I can't create more than 226 LVs.

Is there a patch that allows this limit to be broken?  Should I be using 
a newer version of the tools?  If not currently possible, is this 
something that will be in the near future?

Thanks for any help/advice you can give.

-Nate Stahl

Re: [linux-lvm] How do you create large numbers of LVs? (In the 1000s) Is it even possible?

[Ming Zhang]

On Thu, 2005-07-28 at 12:09 -0700, Nathaniel Stahl wrote:
> We'd like to be able to create a large number of LVs (potentially 
> numbering in the low thousands).  I get failure after LV 226 or so, 
> though - "VG VolGroup01 metadata writing failed".
> 
> RedHat claims this should be possible with LVM2 on the following web page:
> 
> http://www.redhat.com/magazine/009jul05/features/lvm2/
> 
> I admit to being a little suprised at the 2^32 max LV claim - I was 
> figuring 2^20 as the theoretical max given 2.6's 32 bit device numbering 
> scheme (20 bits for minor, 12 bits for major).
> 
> The LVM2 code, at least version 2.00.25 as distributed in FC3, appears 
> to have a check that the minor number is strictly less than 256.  
> Removing this check allows for the creation of working LVs using minors 
> greater than 256, but LV creation fails with the error "VG VolGroup01 
> metadata writing failed" creating the 227th LV.  Even with the minor 
> limit in place - I can't create more than 226 LVs.

i asked this question before. there is a hard coded limitation in lvm
metadata, so the real number is like this, limited around 2xx. the
limitation will be removed in near future. how near? i do not know. :)


> 
> Is there a patch that allows this limit to be broken?  Should I be using 
> a newer version of the tools?  If not currently possible, is this 
> something that will be in the near future?
> 
> Thanks for any help/advice you can give.
> 
> -Nate Stahl
> 
> _______________________________________________
> 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/

Re: [linux-lvm] How do you create large numbers of LVs? (In the 1000s) Is it even possible?

[Jonathan E Brassow]

I think the problem you are seeing is similar to the one found in 
bugzilla (164198).  Would you be willing to add some notes there?  It 
will give you a place to track the progress...

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=164198

  brassow

On Jul 28, 2005, at 2:18 PM, Ming Zhang wrote:

> On Thu, 2005-07-28 at 12:09 -0700, Nathaniel Stahl wrote:
>> We'd like to be able to create a large number of LVs (potentially
>> numbering in the low thousands).  I get failure after LV 226 or so,
>> though - "VG VolGroup01 metadata writing failed".
>>
>> RedHat claims this should be possible with LVM2 on the following web 
>> page:
>>
>> http://www.redhat.com/magazine/009jul05/features/lvm2/
>>
>> I admit to being a little suprised at the 2^32 max LV claim - I was
>> figuring 2^20 as the theoretical max given 2.6's 32 bit device 
>> numbering
>> scheme (20 bits for minor, 12 bits for major).
>>
>> The LVM2 code, at least version 2.00.25 as distributed in FC3, appears
>> to have a check that the minor number is strictly less than 256.
>> Removing this check allows for the creation of working LVs using 
>> minors
>> greater than 256, but LV creation fails with the error "VG VolGroup01
>> metadata writing failed" creating the 227th LV.  Even with the minor
>> limit in place - I can't create more than 226 LVs.
>
> i asked this question before. there is a hard coded limitation in lvm
> metadata, so the real number is like this, limited around 2xx. the
> limitation will be removed in near future. how near? i do not know. :)
>
>
>>
>> Is there a patch that allows this limit to be broken?  Should I be 
>> using
>> a newer version of the tools?  If not currently possible, is this
>> something that will be in the near future?
>>
>> Thanks for any help/advice you can give.
>>
>> -Nate Stahl
>>
>> _______________________________________________
>> 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/
>
> _______________________________________________
> 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/
>

Re: [linux-lvm] How do you create large numbers of LVs? (In the 1000s) Is it even possible?

[Ming Zhang]

i think this is strange that this guy can at least create 1500 lv but
fail to activate them all.

here what i found is i even can not create ~300 lv.


ming


On Thu, 2005-07-28 at 15:32 -0500, Jonathan E Brassow wrote:
> I think the problem you are seeing is similar to the one found in 
> bugzilla (164198).  Would you be willing to add some notes there?  It 
> will give you a place to track the progress...
> 
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=164198
> 
>   brassow
> 
> On Jul 28, 2005, at 2:18 PM, Ming Zhang wrote:
> 
> > On Thu, 2005-07-28 at 12:09 -0700, Nathaniel Stahl wrote:
> >> We'd like to be able to create a large number of LVs (potentially
> >> numbering in the low thousands).  I get failure after LV 226 or so,
> >> though - "VG VolGroup01 metadata writing failed".
> >>
> >> RedHat claims this should be possible with LVM2 on the following web 
> >> page:
> >>
> >> http://www.redhat.com/magazine/009jul05/features/lvm2/
> >>
> >> I admit to being a little suprised at the 2^32 max LV claim - I was
> >> figuring 2^20 as the theoretical max given 2.6's 32 bit device 
> >> numbering
> >> scheme (20 bits for minor, 12 bits for major).
> >>
> >> The LVM2 code, at least version 2.00.25 as distributed in FC3, appears
> >> to have a check that the minor number is strictly less than 256.
> >> Removing this check allows for the creation of working LVs using 
> >> minors
> >> greater than 256, but LV creation fails with the error "VG VolGroup01
> >> metadata writing failed" creating the 227th LV.  Even with the minor
> >> limit in place - I can't create more than 226 LVs.
> >
> > i asked this question before. there is a hard coded limitation in lvm
> > metadata, so the real number is like this, limited around 2xx. the
> > limitation will be removed in near future. how near? i do not know. :)
> >
> >
> >>
> >> Is there a patch that allows this limit to be broken?  Should I be 
> >> using
> >> a newer version of the tools?  If not currently possible, is this
> >> something that will be in the near future?
> >>
> >> Thanks for any help/advice you can give.
> >>
> >> -Nate Stahl
> >>
> >> _______________________________________________
> >> 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/
> >
> > _______________________________________________
> > 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/
> >
> 

Re: [linux-lvm] How do you create large numbers of LVs? (In the 1000s) Is it even possible?

[Jonathan E Brassow]

yeah...  it could be a memory issue which is causing the difference in 
active lvs.

It could be the fact that he starts with _inactive_ lvs that allows him 
to create so many to start.

To see if you are experiencing the same bug, you could 'vgchange -an 
<vol_name>' and then try to create a bunch of lvs...  Then, once 
created, try to activate them.

  brassow

On Jul 28, 2005, at 3:38 PM, Ming Zhang wrote:

> i think this is strange that this guy can at least create 1500 lv but
> fail to activate them all.
>
> here what i found is i even can not create ~300 lv.
>
>
> ming
>
>
> On Thu, 2005-07-28 at 15:32 -0500, Jonathan E Brassow wrote:
>> I think the problem you are seeing is similar to the one found in
>> bugzilla (164198).  Would you be willing to add some notes there?  It
>> will give you a place to track the progress...
>>
>> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=164198
>>
>>   brassow
>>
>> On Jul 28, 2005, at 2:18 PM, Ming Zhang wrote:
>>
>>> On Thu, 2005-07-28 at 12:09 -0700, Nathaniel Stahl wrote:
>>>> We'd like to be able to create a large number of LVs (potentially
>>>> numbering in the low thousands).  I get failure after LV 226 or so,
>>>> though - "VG VolGroup01 metadata writing failed".
>>>>
>>>> RedHat claims this should be possible with LVM2 on the following web
>>>> page:
>>>>
>>>> http://www.redhat.com/magazine/009jul05/features/lvm2/
>>>>
>>>> I admit to being a little suprised at the 2^32 max LV claim - I was
>>>> figuring 2^20 as the theoretical max given 2.6's 32 bit device
>>>> numbering
>>>> scheme (20 bits for minor, 12 bits for major).
>>>>
>>>> The LVM2 code, at least version 2.00.25 as distributed in FC3, 
>>>> appears
>>>> to have a check that the minor number is strictly less than 256.
>>>> Removing this check allows for the creation of working LVs using
>>>> minors
>>>> greater than 256, but LV creation fails with the error "VG 
>>>> VolGroup01
>>>> metadata writing failed" creating the 227th LV.  Even with the minor
>>>> limit in place - I can't create more than 226 LVs.
>>>
>>> i asked this question before. there is a hard coded limitation in lvm
>>> metadata, so the real number is like this, limited around 2xx. the
>>> limitation will be removed in near future. how near? i do not know. 
>>> :)
>>>
>>>
>>>>
>>>> Is there a patch that allows this limit to be broken?  Should I be
>>>> using
>>>> a newer version of the tools?  If not currently possible, is this
>>>> something that will be in the near future?
>>>>
>>>> Thanks for any help/advice you can give.
>>>>
>>>> -Nate Stahl
>>>>
>>>> _______________________________________________
>>>> 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/
>>>
>>> _______________________________________________
>>> 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/
>>>
>>
>

Re: [linux-lvm] How do you create large numbers of LVs? (In the 1000s) Is it even possible?

[Ming Zhang]

I did vgchange -an vg1

and then still fail

[root@fc3-i386-2 ~]# lvcreate -L12M -ntv282 vg1
  VG vg1 metadata writing failed
[root@fc3-i386-2 ~]# lvcreate -vvvvv -L12M -ntv282 vg1
      Setting global/locking_type to 1
      Setting global/locking_dir to /var/lock/lvm
      File-based locking enabled.
      Getting target version for linear
        dm version
        dm versions
      Getting target version for striped
        dm versions
      Locking /var/lock/lvm/V_vg1 WB
    Finding volume group "vg1"
        Opened /dev/sda
      /dev/sda: No label detected
        Opened /dev/md0
        /dev/md0: Failed to read label area
        Opened /dev/sda1
      /dev/sda1: No label detected
        Opened /dev/sda2
      /dev/sda2: No label detected
        Opened /dev/sda3
      /dev/sda3: No label detected
        Opened /dev/sdb
      /dev/sdb: No label detected
        Opened /dev/sdb1
      /dev/sdb1: lvm2 label detected
      /dev/sdb1: lvm2 label detected
        Read vg1 metadata (710) from /dev/sdb1 at 50688 size 65377
    Creating logical volume tv282
        Allowing allocation on /dev/sdb1 start PE 843 length 180
    Archiving volume group "vg1" metadata.
  VG vg1 metadata writing failed
      Unlocking /var/lock/lvm/V_vg1
        Closed /dev/sda
        Closed /dev/md0
        Closed /dev/sda1
        Closed /dev/sda2
        Closed /dev/sda3
        Closed /dev/sdb
        Closed /dev/sdb1

i use this script to create them

#!/bin/bash
# a simple loop to create large # of LV

LIMIT=300
a=1

while [ "$a" -le $LIMIT ]
do
        lvcreate -L10M -ntv$a vg1
        free
        let "a+=1"
done

not ram problem


[root@fc3-i386-2 ~]# free
             total       used       free     shared    buffers
cached
Mem:        255044      80704     174340          0      17776
47400
-/+ buffers/cache:      15528     239516
Swap:       522104          0     522104

[root@fc3-i386-2 ~]# lvextend --version
  LVM version:     2.00.25 (2004-09-29)
  Library version: 1.00.19-ioctl (2004-07-03)
  Driver version:  4.4.0

shall i try new version?

ming


On Thu, 2005-07-28 at 15:49 -0500, Jonathan E Brassow wrote:
> yeah...  it could be a memory issue which is causing the difference in 
> active lvs.
> 
> It could be the fact that he starts with _inactive_ lvs that allows him 
> to create so many to start.
> 
> To see if you are experiencing the same bug, you could 'vgchange -an 
> <vol_name>' and then try to create a bunch of lvs...  Then, once 
> created, try to activate them.
> 
>   brassow
> 
> On Jul 28, 2005, at 3:38 PM, Ming Zhang wrote:
> 
> > i think this is strange that this guy can at least create 1500 lv but
> > fail to activate them all.
> >
> > here what i found is i even can not create ~300 lv.
> >
> >
> > ming
> >
> >
> > On Thu, 2005-07-28 at 15:32 -0500, Jonathan E Brassow wrote:
> >> I think the problem you are seeing is similar to the one found in
> >> bugzilla (164198).  Would you be willing to add some notes there?  It
> >> will give you a place to track the progress...
> >>
> >> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=164198
> >>
> >>   brassow
> >>
> >> On Jul 28, 2005, at 2:18 PM, Ming Zhang wrote:
> >>
> >>> On Thu, 2005-07-28 at 12:09 -0700, Nathaniel Stahl wrote:
> >>>> We'd like to be able to create a large number of LVs (potentially
> >>>> numbering in the low thousands).  I get failure after LV 226 or so,
> >>>> though - "VG VolGroup01 metadata writing failed".
> >>>>
> >>>> RedHat claims this should be possible with LVM2 on the following web
> >>>> page:
> >>>>
> >>>> http://www.redhat.com/magazine/009jul05/features/lvm2/
> >>>>
> >>>> I admit to being a little suprised at the 2^32 max LV claim - I was
> >>>> figuring 2^20 as the theoretical max given 2.6's 32 bit device
> >>>> numbering
> >>>> scheme (20 bits for minor, 12 bits for major).
> >>>>
> >>>> The LVM2 code, at least version 2.00.25 as distributed in FC3, 
> >>>> appears
> >>>> to have a check that the minor number is strictly less than 256.
> >>>> Removing this check allows for the creation of working LVs using
> >>>> minors
> >>>> greater than 256, but LV creation fails with the error "VG 
> >>>> VolGroup01
> >>>> metadata writing failed" creating the 227th LV.  Even with the minor
> >>>> limit in place - I can't create more than 226 LVs.
> >>>
> >>> i asked this question before. there is a hard coded limitation in lvm
> >>> metadata, so the real number is like this, limited around 2xx. the
> >>> limitation will be removed in near future. how near? i do not know. 
> >>> :)
> >>>
> >>>
> >>>>
> >>>> Is there a patch that allows this limit to be broken?  Should I be
> >>>> using
> >>>> a newer version of the tools?  If not currently possible, is this
> >>>> something that will be in the near future?
> >>>>
> >>>> Thanks for any help/advice you can give.
> >>>>
> >>>> -Nate Stahl
> >>>>
> >>>> _______________________________________________
> >>>> 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/
> >>>
> >>> _______________________________________________
> >>> 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/
> >>>
> >>
> >
> 
> _______________________________________________
> 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/

Re: [linux-lvm] How do you create large numbers of LVs? (In the 1000s) Is it even possible?

[Jonathan E Brassow]

I know that a similar bug (158687) has been fixed since your version... 
  It is a somewhat similar bug, but I think the previously mentioned 
applies to you more.  Still, it couldn't hurt to update.

   brassow

On Jul 28, 2005, at 4:26 PM, Ming Zhang wrote:

> I did vgchange -an vg1
>
> and then still fail
>
> [root@fc3-i386-2 ~]# lvcreate -L12M -ntv282 vg1
>   VG vg1 metadata writing failed
> [root@fc3-i386-2 ~]# lvcreate -vvvvv -L12M -ntv282 vg1
>       Setting global/locking_type to 1
>       Setting global/locking_dir to /var/lock/lvm
>       File-based locking enabled.
>       Getting target version for linear
>         dm version
>         dm versions
>       Getting target version for striped
>         dm versions
>       Locking /var/lock/lvm/V_vg1 WB
>     Finding volume group "vg1"
>         Opened /dev/sda
>       /dev/sda: No label detected
>         Opened /dev/md0
>         /dev/md0: Failed to read label area
>         Opened /dev/sda1
>       /dev/sda1: No label detected
>         Opened /dev/sda2
>       /dev/sda2: No label detected
>         Opened /dev/sda3
>       /dev/sda3: No label detected
>         Opened /dev/sdb
>       /dev/sdb: No label detected
>         Opened /dev/sdb1
>       /dev/sdb1: lvm2 label detected
>       /dev/sdb1: lvm2 label detected
>         Read vg1 metadata (710) from /dev/sdb1 at 50688 size 65377
>     Creating logical volume tv282
>         Allowing allocation on /dev/sdb1 start PE 843 length 180
>     Archiving volume group "vg1" metadata.
>   VG vg1 metadata writing failed
>       Unlocking /var/lock/lvm/V_vg1
>         Closed /dev/sda
>         Closed /dev/md0
>         Closed /dev/sda1
>         Closed /dev/sda2
>         Closed /dev/sda3
>         Closed /dev/sdb
>         Closed /dev/sdb1
>
> i use this script to create them
>
> #!/bin/bash
> # a simple loop to create large # of LV
>
> LIMIT=300
> a=1
>
> while [ "$a" -le $LIMIT ]
> do
>         lvcreate -L10M -ntv$a vg1
>         free
>         let "a+=1"
> done
>
> not ram problem
>
>
> [root@fc3-i386-2 ~]# free
>              total       used       free     shared    buffers
> cached
> Mem:        255044      80704     174340          0      17776
> 47400
> -/+ buffers/cache:      15528     239516
> Swap:       522104          0     522104
>
> [root@fc3-i386-2 ~]# lvextend --version
>   LVM version:     2.00.25 (2004-09-29)
>   Library version: 1.00.19-ioctl (2004-07-03)
>   Driver version:  4.4.0
>
> shall i try new version?
>
> ming
>
>
> On Thu, 2005-07-28 at 15:49 -0500, Jonathan E Brassow wrote:
>> yeah...  it could be a memory issue which is causing the difference in
>> active lvs.
>>
>> It could be the fact that he starts with _inactive_ lvs that allows 
>> him
>> to create so many to start.
>>
>> To see if you are experiencing the same bug, you could 'vgchange -an
>> <vol_name>' and then try to create a bunch of lvs...  Then, once
>> created, try to activate them.
>>
>>   brassow
>>
>> On Jul 28, 2005, at 3:38 PM, Ming Zhang wrote:
>>
>>> i think this is strange that this guy can at least create 1500 lv but
>>> fail to activate them all.
>>>
>>> here what i found is i even can not create ~300 lv.
>>>
>>>
>>> ming
>>>
>>>
>>> On Thu, 2005-07-28 at 15:32 -0500, Jonathan E Brassow wrote:
>>>> I think the problem you are seeing is similar to the one found in
>>>> bugzilla (164198).  Would you be willing to add some notes there?  
>>>> It
>>>> will give you a place to track the progress...
>>>>
>>>> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=164198
>>>>
>>>>   brassow
>>>>
>>>> On Jul 28, 2005, at 2:18 PM, Ming Zhang wrote:
>>>>
>>>>> On Thu, 2005-07-28 at 12:09 -0700, Nathaniel Stahl wrote:
>>>>>> We'd like to be able to create a large number of LVs (potentially
>>>>>> numbering in the low thousands).  I get failure after LV 226 or 
>>>>>> so,
>>>>>> though - "VG VolGroup01 metadata writing failed".
>>>>>>
>>>>>> RedHat claims this should be possible with LVM2 on the following 
>>>>>> web
>>>>>> page:
>>>>>>
>>>>>> http://www.redhat.com/magazine/009jul05/features/lvm2/
>>>>>>
>>>>>> I admit to being a little suprised at the 2^32 max LV claim - I 
>>>>>> was
>>>>>> figuring 2^20 as the theoretical max given 2.6's 32 bit device
>>>>>> numbering
>>>>>> scheme (20 bits for minor, 12 bits for major).
>>>>>>
>>>>>> The LVM2 code, at least version 2.00.25 as distributed in FC3,
>>>>>> appears
>>>>>> to have a check that the minor number is strictly less than 256.
>>>>>> Removing this check allows for the creation of working LVs using
>>>>>> minors
>>>>>> greater than 256, but LV creation fails with the error "VG
>>>>>> VolGroup01
>>>>>> metadata writing failed" creating the 227th LV.  Even with the 
>>>>>> minor
>>>>>> limit in place - I can't create more than 226 LVs.
>>>>>
>>>>> i asked this question before. there is a hard coded limitation in 
>>>>> lvm
>>>>> metadata, so the real number is like this, limited around 2xx. the
>>>>> limitation will be removed in near future. how near? i do not know.
>>>>> :)
>>>>>
>>>>>
>>>>>>
>>>>>> Is there a patch that allows this limit to be broken?  Should I be
>>>>>> using
>>>>>> a newer version of the tools?  If not currently possible, is this
>>>>>> something that will be in the near future?
>>>>>>
>>>>>> Thanks for any help/advice you can give.
>>>>>>
>>>>>> -Nate Stahl
>>>>>>
>>>>>> _______________________________________________
>>>>>> 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/
>>>>>
>>>>> _______________________________________________
>>>>> 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/
>>>>>
>>>>
>>>
>>
>> _______________________________________________
>> 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/
>
> _______________________________________________
> 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/
>

Re: [linux-lvm] How do you create large numbers of LVs? (In the 1000s) Is it even possible?

[Ming Zhang]

thx for the information. seem fedora core 3 does not provide update to
lvm adn dm stuff. i will compile from scratch and try later.

ming

On Thu, 2005-07-28 at 17:00 -0500, Jonathan E Brassow wrote:
> I know that a similar bug (158687) has been fixed since your version... 
>   It is a somewhat similar bug, but I think the previously mentioned 
> applies to you more.  Still, it couldn't hurt to update.
> 
>    brassow
> 
> On Jul 28, 2005, at 4:26 PM, Ming Zhang wrote:
> 
> > I did vgchange -an vg1
> >
> > and then still fail
> >
> > [root@fc3-i386-2 ~]# lvcreate -L12M -ntv282 vg1
> >   VG vg1 metadata writing failed
> > [root@fc3-i386-2 ~]# lvcreate -vvvvv -L12M -ntv282 vg1
> >       Setting global/locking_type to 1
> >       Setting global/locking_dir to /var/lock/lvm
> >       File-based locking enabled.
> >       Getting target version for linear
> >         dm version
> >         dm versions
> >       Getting target version for striped
> >         dm versions
> >       Locking /var/lock/lvm/V_vg1 WB
> >     Finding volume group "vg1"
> >         Opened /dev/sda
> >       /dev/sda: No label detected
> >         Opened /dev/md0
> >         /dev/md0: Failed to read label area
> >         Opened /dev/sda1
> >       /dev/sda1: No label detected
> >         Opened /dev/sda2
> >       /dev/sda2: No label detected
> >         Opened /dev/sda3
> >       /dev/sda3: No label detected
> >         Opened /dev/sdb
> >       /dev/sdb: No label detected
> >         Opened /dev/sdb1
> >       /dev/sdb1: lvm2 label detected
> >       /dev/sdb1: lvm2 label detected
> >         Read vg1 metadata (710) from /dev/sdb1 at 50688 size 65377
> >     Creating logical volume tv282
> >         Allowing allocation on /dev/sdb1 start PE 843 length 180
> >     Archiving volume group "vg1" metadata.
> >   VG vg1 metadata writing failed
> >       Unlocking /var/lock/lvm/V_vg1
> >         Closed /dev/sda
> >         Closed /dev/md0
> >         Closed /dev/sda1
> >         Closed /dev/sda2
> >         Closed /dev/sda3
> >         Closed /dev/sdb
> >         Closed /dev/sdb1
> >
> > i use this script to create them
> >
> > #!/bin/bash
> > # a simple loop to create large # of LV
> >
> > LIMIT=300
> > a=1
> >
> > while [ "$a" -le $LIMIT ]
> > do
> >         lvcreate -L10M -ntv$a vg1
> >         free
> >         let "a+=1"
> > done
> >
> > not ram problem
> >
> >
> > [root@fc3-i386-2 ~]# free
> >              total       used       free     shared    buffers
> > cached
> > Mem:        255044      80704     174340          0      17776
> > 47400
> > -/+ buffers/cache:      15528     239516
> > Swap:       522104          0     522104
> >
> > [root@fc3-i386-2 ~]# lvextend --version
> >   LVM version:     2.00.25 (2004-09-29)
> >   Library version: 1.00.19-ioctl (2004-07-03)
> >   Driver version:  4.4.0
> >
> > shall i try new version?
> >
> > ming
> >
> >
> > On Thu, 2005-07-28 at 15:49 -0500, Jonathan E Brassow wrote:
> >> yeah...  it could be a memory issue which is causing the difference in
> >> active lvs.
> >>
> >> It could be the fact that he starts with _inactive_ lvs that allows 
> >> him
> >> to create so many to start.
> >>
> >> To see if you are experiencing the same bug, you could 'vgchange -an
> >> <vol_name>' and then try to create a bunch of lvs...  Then, once
> >> created, try to activate them.
> >>
> >>   brassow
> >>
> >> On Jul 28, 2005, at 3:38 PM, Ming Zhang wrote:
> >>
> >>> i think this is strange that this guy can at least create 1500 lv but
> >>> fail to activate them all.
> >>>
> >>> here what i found is i even can not create ~300 lv.
> >>>
> >>>
> >>> ming
> >>>
> >>>
> >>> On Thu, 2005-07-28 at 15:32 -0500, Jonathan E Brassow wrote:
> >>>> I think the problem you are seeing is similar to the one found in
> >>>> bugzilla (164198).  Would you be willing to add some notes there?  
> >>>> It
> >>>> will give you a place to track the progress...
> >>>>
> >>>> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=164198
> >>>>
> >>>>   brassow
> >>>>
> >>>> On Jul 28, 2005, at 2:18 PM, Ming Zhang wrote:
> >>>>
> >>>>> On Thu, 2005-07-28 at 12:09 -0700, Nathaniel Stahl wrote:
> >>>>>> We'd like to be able to create a large number of LVs (potentially
> >>>>>> numbering in the low thousands).  I get failure after LV 226 or 
> >>>>>> so,
> >>>>>> though - "VG VolGroup01 metadata writing failed".
> >>>>>>
> >>>>>> RedHat claims this should be possible with LVM2 on the following 
> >>>>>> web
> >>>>>> page:
> >>>>>>
> >>>>>> http://www.redhat.com/magazine/009jul05/features/lvm2/
> >>>>>>
> >>>>>> I admit to being a little suprised at the 2^32 max LV claim - I 
> >>>>>> was
> >>>>>> figuring 2^20 as the theoretical max given 2.6's 32 bit device
> >>>>>> numbering
> >>>>>> scheme (20 bits for minor, 12 bits for major).
> >>>>>>
> >>>>>> The LVM2 code, at least version 2.00.25 as distributed in FC3,
> >>>>>> appears
> >>>>>> to have a check that the minor number is strictly less than 256.
> >>>>>> Removing this check allows for the creation of working LVs using
> >>>>>> minors
> >>>>>> greater than 256, but LV creation fails with the error "VG
> >>>>>> VolGroup01
> >>>>>> metadata writing failed" creating the 227th LV.  Even with the 
> >>>>>> minor
> >>>>>> limit in place - I can't create more than 226 LVs.
> >>>>>
> >>>>> i asked this question before. there is a hard coded limitation in 
> >>>>> lvm
> >>>>> metadata, so the real number is like this, limited around 2xx. the
> >>>>> limitation will be removed in near future. how near? i do not know.
> >>>>> :)
> >>>>>
> >>>>>
> >>>>>>
> >>>>>> Is there a patch that allows this limit to be broken?  Should I be
> >>>>>> using
> >>>>>> a newer version of the tools?  If not currently possible, is this
> >>>>>> something that will be in the near future?
> >>>>>>
> >>>>>> Thanks for any help/advice you can give.
> >>>>>>
> >>>>>> -Nate Stahl
> >>>>>>
> >>>>>> _______________________________________________
> >>>>>> 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/
> >>>>>
> >>>>> _______________________________________________
> >>>>> 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/
> >>>>>
> >>>>
> >>>
> >>
> >> _______________________________________________
> >> 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/
> >
> > _______________________________________________
> > 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/
> >
> 
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