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

[Jonathan E Brassow <jbrassow@redhat.com>]

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
>>>>
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>>>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>>>
>>> _______________________________________________
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>>>
>>
>