The process and thinking of reducing and enlarging LV in Linux

Today in the installation of Oracle one RAC, look at the operating system DF-LH, found that the/home directory has been divided into more than 500 g,/root directory only 50G, then I burst a foul language, the TM system is how to do.

Filesystem Size used Avail use% mounted on

/dev/mapper/vg_db5-lv_root 50G 6.2G 41G 14%/

Tmpfs 127G 84K 127G 1%/DEV/SHM

/DEV/SDQ1 477M 37M 415M 9%/boot

/dev/mapper/vg_db5-lv_home 496G 70M 471G 1%/Home

#vgdisplay

---Volume Group---

VG Name VG_DB5

System ID

Format lvm2

Metadata Areas 1

Metadata Sequence No 4

VG Access Read/write

VG Status resizable

MAX LV 0

Cur LV 3

Open LV 3

Max PV 0

Cur PV 1

ACT PV 1

VG Size 557.26 GiB

PE Size 4.00 MiB

Total PE 142658

Alloc pe/size 142658/557.26 GiB

Free Pe/size 0/0

VG UUID Plc2k9-lrvy-bcck-b9qp-3f8k-h6cw-w4vrds

#lvdisplay

---Logical volume---

LV Path/dev/vg_db6/lv_root

LV Name Lv_root

VG Name VG_DB6

LV UUID 6hlvnp-6rgm-korq-eox6-nqqv-8pwb-gg4wne

LV Write Access Read/write

LV Creation Host, Time DB6, 2015-02-02 19:25:11 +0800

LV Status Available

# open 1

LV Size 50.00 GiB

Current LE 12800

Segments 1

Allocation inherit

Read ahead Sectors Auto

-Currently set to 256

Block Device 253:0

---Logical volume---

LV Path/dev/vg_db6/lv_home

LV Name Lv_home

VG Name VG_DB6

LV UUID yubjai-96d6-jfwx-cmxr-eexe-cuuu-uqrl3l

LV Write Access Read/write

LV Creation Host, Time DB6, 2015-02-02 19:25:17 +0800

LV Status Available

# open 1

LV Size 503.26 GiB

Current LE 128834

Segments 1

Allocation inherit

Read ahead Sectors Auto

-Currently set to 256

Block Device 253:10

---Logical volume---

LV Path/dev/vg_db6/lv_swap

LV Name Lv_swap

VG Name VG_DB6

LV UUID D5fqb1-tthm-hsrb-b0tm-r1ms-xnvp-dh5ovs

LV Write Access Read/write

LV Creation Host, Time DB6, 2015-02-02 19:27:23 +0800

LV Status Available

# open 1

LV Size 4.00 GiB

Current LE 1024

Segments 1

Allocation inherit

Read ahead Sectors Auto

-Currently set to 256

Block Device 253:1

There were three LV in a VG, which decided to adjust the size of these three lv. Turn the Lv_home small, then turn the lv_root up. Note that there is a risk of narrowing the space, so I first delete the Oracle,grid user and all the groups inside, and then restart the system.

#userdel Oracle

#userdel Grid

#groudel Oinstall

....................

After rebooting, check the/ETC/GROUP,/ETC/PASSWD, confirm that there are no users and groups, we can start.

1. #umount/home1. #umount/Home

If unsuccessful, an error may occur, the workaround is as follows: Umount:/mnt/cdrom:device is busy.

(In some cases useful info about processes that

Use the device are found by lsof (8) or user (1))

#umount/mnt/cdrom/-f//forced unload also not

Umount2: Device or resource busy

Umount:/mnt:device is busy.

(In some cases useful info about processes

The device is found by lsof (8) or fuser (1)) Umount2: Devices or resources are busy

#fuser-M/home

/home:1338c

# PS aux |grep 1338

Root 1338 0.0 0.2 108292 1912 PTS/2 ss+ 14:27 0:00-bash

Root 1423 0.0 0.1 103236 884 pts/1 s+ 14:49 0:00 grep 1338

#kill-9 1338

#fuser-M/home

#umount/Home

Parsing: But the feeling that this method is only used for those insignificant directories, because the process uses less, if it is/directory, the process will not kill, kill, the system is estimated to collapse.

Reduction of logical volumes, risk, first reducing logical boundaries--reducing physical boundaries

Note: 1, can not be reduced online, you have to uninstall first;

2, to ensure that the size of the reduced space can still store all the original data;

3, before the reduction should be forced to check the file, to ensure that the file system in a consistent state

2. Check

#e2fsck-F/dev/vg_db5/lv_home

E2fsck 1.41.12 (17-may-2010)

First step: Check Inode, block, and size

Step Two: Check the directory structure

3rd Step: Check the directory connectivity

Pass 4:checking Reference counts

5th Step: Check Cluster summary information

/dev/vg_db5/lv_home:29/32989184 files (0.0% non-contiguous), 2121120/131926016 blocks

3. Start shrinking the file system:

#resize2fs/dev/vg_db5/lv_home 1024M

RESIZE2FS 1.41.12 (17-may-2010)

Resize2fs:new size smaller than minimum (307344)

Display 1G is too small, the minimum is 307,344 blocks. Come on, 10 g.

#resize2fs/dev/vg_db5/lv_home 10G

RESIZE2FS 1.41.12 (17-may-2010)

Resizing the filesystem on/dev/vg_db5/lv_home to 2621440 (4k) blocks.

The filesystem on/dev/vg_db5/lv_home is now 2621440 blocks long.

4. Reduce the LV size:

# lvreduce-l 10g/dev/vg_db5/lv_home

Warning:reducing active Logical Volume to 10.00 GiB

This May DESTROY YOUR DATA (filesystem etc)

Does really want to reduce lv_home? [y/n]: Y

Size of logical volume Vg_db5/lv_home changed from 503.26 Gib (128834 extents) to 10.00 GIB (2560 extents).

Logical Volume Lv_home successfully resized

#vgdisplay found out the space has been released.

---Volume Group---

VG Name VG_DB5

System ID

Format lvm2

Metadata Areas 1

Metadata Sequence No 5

VG Access Read/write

VG Status resizable

MAX LV 0

Cur LV 3

Open LV 2

Max PV 0

Cur PV 1

ACT PV 1

VG Size 557.26 GiB

PE Size 4.00 MiB

Total PE 142658

Alloc pe/size 16384/64.00 GiB

Free Pe/size 126274/493.26 GiB

VG UUID JI4TQC-IBHS-O6CB-XH5Q-Q4UK-DIER-DVSMMD

5. Increase the size of the lv:lv_root to 500G

#lvextend-L 500g-f-r/dev/vg_db5/lv_root

Size of logical Volume Vg_db5/lv_root changed from 50.00 Gib (12800 extents) to 500.00 GIB (128000 extents).

Logical Volume Lv_root successfully resized

RESIZE2FS 1.41.12 (17-may-2010)

Filesystem at/dev/mapper/vg_db5-lv_root is mounted on/; On-line resizing required

Old desc_blocks = 4, new_desc_blocks = 32

Performing an on-line resize of/dev/mapper/vg_db5-lv_root to 131072000 (4k) blocks.

The filesystem on/dev/mapper/vg_db5-lv_root is now 131072000 blocks long.

If you want to increase your operating system size again, you don't have to do it.

# Resize2fs/dev/vg_db5/lv_root 500G

RESIZE2FS 1.41.12 (17-may-2010)

The filesystem is already 131072000 blocks long. Nothing to Do!

#resize2fs-P/dev/vg_db5/lv_root

RESIZE2FS 1.41.12 (17-may-2010)

The filesystem is already 131072000 blocks long. Nothing to Do!

After reboot:

#df-LH

Filesystem Size used Avail use% mounted on

/dev/mapper/vg_db5-lv_root 493G 6.2G 461G 2%/

Tmpfs 160G 144K 160G 1%/DEV/SHM

/DEV/SDQ1 477M 37M 415M 9%/boot

/dev/mapper/vg_db5-lv_home 9.8G 37M 9.2G 1%/Home

It's finally done.

For more detailed LVM theory concepts, see the blog:

http://80cto.blog.51cto.com/7503144/1610922

The process and thinking of reducing and increasing LV in Linux