Shrink LMV2 root partition

vinay45 · 04-28-2015, 11:04 AM

please help me with shrinking my centos7 home partition,this partition has taken up all the free space on my hard disk.

T3RM1NVT0R · 04-28-2015, 11:20 AM

Make sure that you have backup of /home partition, reducing lv can sometime result in loss of data. Refer this link for reducing LV: http://www.tecmint.com/extend-and-reduce-lvms-in-linux/

vinay45 · 04-29-2015, 01:33 AM

When i unmount the partition this is what happens :

Quote:

[root@localhost vgeorge]# umount -v /home
umount: /home: target is busy.
(In some cases useful info about processes that use
the device is found by lsof(8) or fuser(1))
[root@localhost vgeorge]#

syg00 · 04-29-2015, 01:39 AM

As it will be when you are logged on. Let's see the output from this (use [code] tags rather than [quote] when posting output)

Code:

df -hT
sudo parted -l

vinay45 · 04-29-2015, 01:57 AM

df -hT:

Code:

Filesystem              Type      Size  Used Avail Use% Mounted on
/dev/mapper/centos-root xfs        50G  4.1G   46G   9% /
devtmpfs                devtmpfs  908M     0  908M   0% /dev
tmpfs                   tmpfs     917M   84K  917M   1% /dev/shm
tmpfs                   tmpfs     917M  8.9M  908M   1% /run
tmpfs                   tmpfs     917M     0  917M   0% /sys/fs/cgroup
/dev/sda6               xfs       494M  143M  352M  29% /boot
/dev/mapper/centos-home xfs       170G  2.3G  167G   2% /home

sudo parted -l

Code:

Model: ATA WDC WD5000AZRX-0 (scsi)
Disk /dev/sda: 500GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags: 

Number  Start   End     Size    Type      File system  Flags
 1      1049kB  367MB   366MB   primary   ntfs
 2      368MB   52.4GB  52.1GB  primary   ntfs         boot
 3      52.4GB  157GB   105GB   primary   ntfs
 4      157GB   500GB   343GB   extended               lba
 5      157GB   262GB   105GB   logical   ntfs
 6      262GB   263GB   524MB   logical   xfs
 7      263GB   500GB   237GB   logical                lvm


Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/centos-home: 182GB
Sector size (logical/physical): 512B/4096B
Partition Table: loop
Disk Flags: 

Number  Start  End    Size   File system  Flags
 1      0.00B  182GB  182GB  xfs


Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/centos-root: 53.7GB
Sector size (logical/physical): 512B/4096B
Partition Table: loop
Disk Flags: 

Number  Start  End     Size    File system  Flags
 1      0.00B  53.7GB  53.7GB  xfs


Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/centos-swap: 2164MB
Sector size (logical/physical): 512B/4096B
Partition Table: loop
Disk Flags: 

Number  Start  End     Size    File system     Flags
 1      0.00B  2164MB  2164MB  linux-swap(v1)

syg00 · 04-29-2015, 02:15 AM

The reason I asked for the df was to see the filesystem type. XFS (the default in CentOS 7) is bad - you can't shrink it like ext[34].
You will have to back it up, delete the lv and reallocate it (I'd suggest ext4) and restore your data.

vinay45 · 04-30-2015, 03:37 AM

Would macrium reflect be enough to back up the partition and restore it to newly created partition.

syg00 · 04-30-2015, 06:48 AM

Never heard of it - try fsarchiver, it validates the data, and you can easily restore to a different filesystem.
Check the site for the quickstart guide.

vinay45 · 05-01-2015, 01:25 PM

fsarchiver gives the following error:

Quote:

filesystem may not be supported by either fsarchiver or the kernel.

syg00 · 05-03-2015, 09:01 PM

Where did you get fsarchiver from - did you use the official repos ?. If so, raise a bug with CentOS.
I did see a problem where systemd seems to cause an issue, but I just tested an XFS partition on Fedora 21 and fsarchiver worked fine.

vinay45 · 11-24-2015, 12:30 PM

Hi
its been a while but i haven't yet solved it.
this tut seems simple enough to give a try here : shrink-xfs-partition-almost-possible
I can't exactly interpret this code :

Code:

pvcreate /dev/vda2
vgcreate fixed_centos_VG /dev/vda2
lvcreate -L 1G -n swap fixed_centos_VG
lvcreate -l 100%FREE -n root fixed_centos_VG
vgchange -a y fixed_centos_VG

how would the above code translate while i should use it,what should i insert instead of

Quote:

fixed_centos_VG