How to resize logical volume in Red Hat Linux

Question

Please guide that how to do following tasks with executing command.

• 1.Create a new physical volume, create a new volume group in the name of dataconresize, vg extent is 16.00MB.
• 2.Create a new logical volume in the name of datacopyresize with the size of 50 extents and file system must ext4
• 3.Then mount it under /dataresize
• 4.Resize the logical volume, logical-data and it filesystem to 400MB.
• 5.Resize the logical volume, logical-data and it filesystem to 600MB. Make sure that the filesystem contents remain intact.

Note: partitions are seldom exactly the size requested,so any thing within the range of 370MB to 430MB is acceptable.

I tried first three steps as follows.

fdisk /dev/vdb 

----- > Create the Partition and set it's type 8e (which is LVM type)

partprobe /dev/vdb  

-----> get the partition

pvcreate /dev/vdb1
vgcreate -s 16M dataconresize /dev/vdb1
vgdisplay  

-----> Check the vg extent size, its should be this (PE Size 16.00 MiB)

lvcreate -l 50 -n datacopyresize dataconresize
lvdisplay

-----> Check the size of extents

mkfs.ext4 /dev/dataconresize/datacopyresize  

-----> Make a filesystem on it

mkdir -p /dataresize  

-----> Create Directory to mount on it

blkid /dev/dataconresize/datacopyresize  

-----> Get the UUID of /dev/datacontainer/datacopy

vim /etc/fstab 

-----> Create the mount point inside the fstab

UUID=C553-2BF5 /dataresize ext4 defaults 0 0  
mount -a

df -hT  

-----> get the mount point of it

But I am stuck with task 4 and task 5.

Answer 1

You have a LV called "datacopyresize" of size PE_size x 50 = 800 Mb.

To shrink it to 400 Mb you will need to resize first the filesystem, then the LV (otherwise you'll lose data):

resize2fs /dev/dataconresize/datacopyresize 400M
lvresize -L 400M /dev/dataconresize/datacopyresize

Then to extend it to 600 Mb, you first resize the LV and then the filesystem:

lvresize -L 600M /dev/dataconresize/datacopyresize
resize2fs /dev/dataconresize/datacopyresize 600M

Note: you could use instead lvreduce to shrink the LV and lvextend to extend it; the advantage of lvresize is that it offers an unique command for both operations.
Also, you could pass the --resizefs argument to lvresize to automatically resize the fs along with the LV, instead of using resize2fs; I suggest you try my method, which uses two separate commands, to better understand what you're doing.