[linux-lvm] 2 TB limit

[linux-lvm] 2 TB limit

[Brad Vrabete]

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Hi,

Is there any was to create a logigal volume larger than 2TB? Can LVM2 do that?

Thanks,

Brad Vrabete

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Re: [linux-lvm] 2 TB limit

[Goetz Bock]

On Thu, Mar 25 '04 at 16:23, Brad Vrabete wrote:
> Is there any was to create a logigal volume larger than 2TB? Can LVM2
> do that?
you need to use 2.6.x (or find a patch for 2.4.x) as onty his kernel
supports large block devices.

Or you might have luck with x86_64 (aka AMD Opterons)
-- 
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Re: [linux-lvm] 2 TB limit

[Delian Krustev]

On Thursday 25 March 2004 23:23, Brad Vrabete wrote:

> Is there any was to create a logigal volume larger than 2TB? Can LVM2 do
> that?

I think it can. However tha maximum size for a block device in 2.4 kernels
is 2TB. You should try 2.6, and use large enough PE size.

Re: [linux-lvm] 2 TB limit

[AJ Lewis]

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On Fri, Mar 26, 2004 at 06:13:50PM +0200, Delian Krustev wrote:
> On Thursday 25 March 2004 23:23, Brad Vrabete wrote:
> 
> > Is there any was to create a logigal volume larger than 2TB? Can LVM2 do
> > that?
> 
> I think it can. However tha maximum size for a block device in 2.4 kernels
> is 2TB. You should try 2.6, and use large enough PE size.

The PE size limitation isn't present in lvm2 (The version of lvm that works
in 2.6) if you use the native lvm2 format.  So you should be able to create
larger than 2TB LVs with LVM2.  Just FYI.

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Re: [linux-lvm] 2 TB limit

[Alasdair G Kergon]

On Fri, Mar 26, 2004 at 10:16:44AM -0600, AJ Lewis wrote:
> The PE size limitation isn't present in lvm2 (The version of lvm that works
> in 2.6) if you use the native lvm2 format.  So you should be able to create
> larger than 2TB LVs with LVM2.  Just FYI.

As those of you monitoring the lvm-cvs mailing list may have noticed, 
I've added code to the LVM2 CVS tree to help people simulate large devices
for testing purposes on 2.6 kernels with the latest -udm patches.

  lvcreate --type zero -L16T vg  # Create 16TB 'zero' device
  lvcreate -s vg/lvol0 -L1G      # Create snapshot of it

Then use the snapshot as a 'sparse' device, in the example, supporting
upto 1GB of actual data.

[At some point I'll merge it into a one-line command with --type sparse]

NB There's been a lot of change in CVS recently (and more to come)
so I expect some new bugs to show up along with the new features:-(
 
Alasdair
-- 
agk@redhat.com

Re: [linux-lvm] 2 TB limit

[P. Larry Nelson]

On 5/12/2004 4:32 PM, Alasdair G Kergon wrote:

> On Fri, Mar 26, 2004 at 10:16:44AM -0600, AJ Lewis wrote:
> 
>>The PE size limitation isn't present in lvm2 (The version of lvm that works
>>in 2.6) if you use the native lvm2 format.  So you should be able to create
>>larger than 2TB LVs with LVM2.  Just FYI.
> 
> 
> As those of you monitoring the lvm-cvs mailing list may have noticed, 
> I've added code to the LVM2 CVS tree to help people simulate large devices
> for testing purposes on 2.6 kernels with the latest -udm patches.
> 
>   lvcreate --type zero -L16T vg  # Create 16TB 'zero' device
>   lvcreate -s vg/lvol0 -L1G      # Create snapshot of it
> 
> Then use the snapshot as a 'sparse' device, in the example, supporting
> upto 1GB of actual data.
> 
> [At some point I'll merge it into a one-line command with --type sparse]
> 
> NB There's been a lot of change in CVS recently (and more to come)
> so I expect some new bugs to show up along with the new features:-(
>  
> Alasdair

Being confined to running RedHat and using their updates and RPMs,
I'm running stock RHEL-ES3 file servers with latest RH kernel of
2.4.21-15.0.4.ELsmp and lvm-1.0.3-15.  I'm led to understand that
the ES3 kernel has portions of the 2.6 kernel in it, but I don't
think it has the portion that can handle >2TB file systems.

I have had a need to go to >2TB file systems for some time and am
sort of limping along by stringing together many 2TB file systems.

Can anyone (perhaps our list contributor from RedHat?) tell me when
I can expect a kernel and lvm from RedHat that will allow me to go
beyond the 2TB limit?

Thanks!
- Larry
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Re: [linux-lvm] 2 TB limit

[Peter Smith]

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P. Larry Nelson wrote:

> On 5/12/2004 4:32 PM, Alasdair G Kergon wrote:
>
>> On Fri, Mar 26, 2004 at 10:16:44AM -0600, AJ Lewis wrote:
>>
>>> The PE size limitation isn't present in lvm2 (The version of lvm 
>>> that works
>>> in 2.6) if you use the native lvm2 format.  So you should be able to 
>>> create
>>> larger than 2TB LVs with LVM2.  Just FYI.
>>
>>
>>
>> As those of you monitoring the lvm-cvs mailing list may have noticed, 
>> I've added code to the LVM2 CVS tree to help people simulate large 
>> devices
>> for testing purposes on 2.6 kernels with the latest -udm patches.
>>
>>   lvcreate --type zero -L16T vg  # Create 16TB 'zero' device
>>   lvcreate -s vg/lvol0 -L1G      # Create snapshot of it
>>
>> Then use the snapshot as a 'sparse' device, in the example, supporting
>> upto 1GB of actual data.
>>
>> [At some point I'll merge it into a one-line command with --type sparse]
>>
>> NB There's been a lot of change in CVS recently (and more to come)
>> so I expect some new bugs to show up along with the new features:-(
>>  
>> Alasdair
>
>
> Being confined to running RedHat and using their updates and RPMs,
> I'm running stock RHEL-ES3 file servers with latest RH kernel of
> 2.4.21-15.0.4.ELsmp and lvm-1.0.3-15.  I'm led to understand that
> the ES3 kernel has portions of the 2.6 kernel in it, but I don't
> think it has the portion that can handle >2TB file systems.
>
> I have had a need to go to >2TB file systems for some time and am
> sort of limping along by stringing together many 2TB file systems.
>
> Can anyone (perhaps our list contributor from RedHat?) tell me when
> I can expect a kernel and lvm from RedHat that will allow me to go
> beyond the 2TB limit?
>
> Thanks!
> - Larry


I happened to look into this over the past few months.  Redhat 
Enterprise Linux v3 does NOT have any support for >2TB _anything_.  
Redhat has told me that >2TB support, which would mean kernel v2.6 (and 
probably LVM2) will only be available when Enterprise v4 comes out.  
Also, v4 is scheduled to be out in probably about 10 more months now, 
maybe less (at the time it was 13-15 months).

HTH

Peter


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