[linux-lvm] Converting existing thick LVs into thin LVs possible?
jeremy at esilo.com
Fri Feb 14 19:21:40 UTC 2014
I have a system currently using LVM2 that was originally set up on
RHEL5 (where thin provisioning was not supported).
This system would greatly benefit from the newer thin provisioning
features, and so I am investigating upgrading to RHEL6 so that I may
take advantage. My question is this: Can I convert existing LVM2
"thick" logical volumes into thinly-provisioned volumes on the fly?
lead me to believe that it is possible:
"You can use the --thinpool parameter of the lvconvert command to
convert an existing logical volume to a thin volume."
with the following:
lvconvert --thinpool vg001/lv1 --poolmetadata vg001/lv2
However, I seem to not understand how that works. From the example, I
would assume that vg001/lv1 is the existing "thick" LV that I want to
convert and that vg001/lv2 is an existing LV with enough space to
become the metadata. So, I create a metadata LV with:
test at testbox:~$ sudo lvcreate -L16G MyVG -n Metadata
Logical volume "Metadata" created
But when I attempt the conversion, I do not get what I would expect:
test at testbox:~$ sudo lvconvert --thinpool MyVG/OldThickLV1
Converted MyVG/OldThickLV1 to thin pool.
Then the OldThickLV1 disappears, leaving Metadata around:
test at testbox:~$ sudo lvdisplay
--- Logical volume ---
LV Name Metadata
VG Name MyVG
LV UUID IZb6zP-D7iD-NswX-XcDZ-K5fN-sGBj-lCMiqO
LV Write Access read/write
LV Creation host, time testbox, 2014-02-14 13:50:04 -0500
LV Pool transaction ID 0
LV Pool metadata Metadata_tmeta
LV Pool data Metadata_tdata
LV Pool chunk size 64.00 KiB
LV Zero new blocks no
LV Status available
# open 0
LV Size 16.00 GiB
Allocated pool data 0.00%
Allocated metadata 0.01%
Current LE 4096
Read ahead sectors auto
- currently set to 256
Block device 252:5
Am I doing something wrong here?
Or am I going to have to create a new thin pool, new thin logical
volumes, and copy the data over?
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