[rhelv6-list] How can I create sparse block devices as a logical volumes with lvm

[John Haxby]

On 4 February 2011 11:45, carlopmart <carlopmart at gmail.com> wrote:

> On 02/04/2011 12:37 PM, John Haxby wrote:
>
>>
>> Do you mean something like this (from the lvcreate man page):
>>
>> "lvcreate --virtualsize 1T --size 100M --snapshot --name sparse vg1"
>>        creates a sparse device named /dev/vg1/sparse of size  1TB  with
>>  space
>>        for just under 100MB of actual data on it.
>>
>>
>> jch
>>
>>
>>
> Yes, but If I understand good, these options are only valid for snapshots
> ... I am trying to do a sparse logical volume without using snapshots ...
>
>

Hmmm.  So you want to create a sparse logical volume using something other
than the mechanism for creating sparse logical volumes?  Quoting the man
page again:

       --virtualsize VirtualSize
              Create a sparse device of the given  size  (in  MB  by
default)
              using  a  snapshot.   Anything  written  to  the  device will
be
              returned when reading from it.  Reading from other areas of
the
              device will return blocks of zeros.  It is implemented by
creat‐
              ing a hidden virtual device of the requested size using the
zero
              target.  A suffix of _vorigin is used for this device.

Actually, I think the "--snapshot" on the man page example I previously
quoted is either redundant or wrong, this command works just fine:

   lvcreate --virtualsize 1T --size 100M --name sparse vg1

Now it doesn't mention the s-word are you happy?

jch
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/rhelv6-list/attachments/20110204/d4f4d2f4/attachment.htm>