How to resize LVM partitions
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01-14-2013, 10:28 AM
(This post was last modified: 11-06-2013 08:58 PM by knifebunny.)
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How to resize LVM partitions
Grow File System
Increasing the size of a file system managed with LVM can be done online (with the file system mounted.) In order to grow the LV and file system: Check to see if free space exists on the LV that contains the file system Expand the LV if it does not contain enough free space (which could require expanding the volume group if it is out of free space) Grow the file system to utilize all available space on the LV Lets get started! First, check the size of the file system to see if it needs expanding Code: [[email protected] ~]# pwd Note: The disk free command shows that we have 65MB available on our file system and that its 98% use. If we don't take action soon, we risk filling the file system. Let's find out which Volume Group contains the Logical Volume that holds /dev/mapper/TCPDumpVolGRP-TCPDumpLV Code: [[email protected] ~]# lvdisplay /dev/TCPDumpVolGRP/TCPDumpLV Note: You can see the volume group for this file system is TCPDumpVolGRP Let's find out if the volume group TCPDumpVolGRP has available free space to allocate to the logical volume Code: [[email protected] ~]# vgdisplay TCPDumpVolGRP Note: This volume group has plenty of free space. If we were out of physical extents, we would have to add additional physical volumes to this volume group before continuing on. We will now resize the logical volume TCPDumpLV by adding 3GB Code: [[email protected] TCPDumpLV]# lvresize -L +3GB /dev/TCPDumpVolGRP/TCPDumpLV Confirm the new size of the logical volume Code: [[email protected] ~]# lvdisplay /dev/TCPDumpVolGRP/TCPDumpLV We now need to resize the ext3 file system to utilize the remaining available space within the logical volume Code: [[email protected] TCPDumpLV]# resize2fs -p /dev/mapper/TCPDumpVolGRP-TCPDumpLV Code: [[email protected] TCPDumpLV]# df -kh . Shrink File System Decreasing the size of a file system managed with LVM must be done off-line (unmounted.) To shrink the file system and LV: Unmount the file system Run a file system check to ensure the integrity of the volume Shrink the file system Shrink the logical volume Note: You cannot shrink the file system beyond the amount of free space that is available on it. So if the file system you want to shrink has 1GB of free space, you will only be able to shrink the volume by 1GB. However, logical volumes are not as forgiving. If you are not careful, you can shrink the LV to a size less than what is required by the file system. If the LV is resized smaller than what the file system has been resized to, things will go very badly for you. Did we mention you should backup your data before hand? Let's get started! First, check to see how much space is available Code: [[email protected] ~]# pwd Note: The disk free command shows that we are using 922MB and have 4.9G available on our file system. Therefore, we can safely shrink the volume to 1.5G (leaving a little bit for overhead) without any issue. Unmount the file system Code: [[email protected] TCPDumpLV]# cd / Code: [[email protected] /]# e2fsck -f /dev/mapper/TCPDumpVolGRP-TCPDumpLV Shrink the file system to 1.5GB Code: [[email protected] /]# resize2fs /dev/mapper/TCPDumpVolGRP-TCPDumpLV 1500M Shrink the logical file system to 1.5GB Code: [[email protected] /]# lvresize -L 1.5G /dev/TCPDumpVolGRP/TCPDumpLV Note: Special precaution should be taken with this step. It's possible to reduce the logical volume size by more than the size of the file system. If you do reduce the LV size by more than what you resized the file system to (from step #4), this will almost certainly end very badly for you. Ensure the LV is large enough for the file system and that you make a backup before hand! Verify the new size of the logical volume Code: [[email protected] ~]# lvdisplay /dev/TCPDumpVolGRP/TCPDumpLV Code: [[email protected] /]# mount /dev/TCPDumpVolGRP/TCPDumpLV Nice work, you've just resized your LV and it's file systems! |
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