You can migrate Volume Groups to another host. Though its not exactly plug-and-play, the procedure to do this is pretty straight-forward. There are dozens of tutorials available online how to do this. This serverfault thread discusses about moving an LVM partition to another host using the dd command. These data structures can be seen below:. From there logical and physical volumes are detailed. Sample metadata contents can be seen below:.
Note if there are multiple physical volumes in the volume group, be sure to extract all metadata from as mappings may result in blocks being cross-referenced. To lookup a logical address, first determine which logical volume segment range the address falls into. To extend an LV there must be enough unallocated space available on the VG.
The recommended way to grow or shrink a logical volume is to use the YaST Partitioner. When using YaST, the size of the file system in the volume will automatically be adjusted, too. LVs can be extended or shrunk manually while they are being used, but this may not be true for a file system on them.
Extending or shrinking the LV does not automatically modify the size of file systems in the volume. You must use a different command to grow the file system afterward.
For information about resizing file systems, see Chapter 2, Resizing File Systems. If you extend an LV, you must extend the LV before you attempt to grow the file system. If you shrink an LV, you must shrink the file system before you attempt to shrink the LV. If the logical volume contains an Ext2 or Ext4 file system, which do not support online growing, dismount it. In case it contains file systems that are hosted for a virtual machine such as a Xen VM , shut down the VM first.
At the terminal console prompt, enter the following command to grow the size of the logical volume:. For example:. Adjust the size of the file system. If the logical volume does not contain a Btrfs file system, dismount it. Note that volumes with the XFS file system cannot be reduced in size. At the terminal console prompt, enter the following command to shrink the size of the logical volume to the size of the file system:.
Starting with SUSE Linux Enterprise Server 12 SP1, lvextend , lvresize , and lvreduce support the option --resizefs which will not only change the size of the volume, but will also resize the file system. Therefore the examples for lvextend and lvreduce shown above can alternatively be run as follows:. With the current LVM design, if this information is not available, LVM must scan all the physical disk devices in the system. In case a disk fails to respond, LVM commands might run into a timeout while waiting for the disk.
Dynamic aggregation of LVM metadata via lvmetad provides a solution for this problem. The purpose of the lvmetad daemon is to eliminate the need for this scanning by dynamically aggregating metadata information each time the status of a device changes. These events are signaled to lvmetad by udev rules. If the daemon is not running, LVM performs a scan as it normally would do. This feature is enabled by default. In case it is disabled on your system, proceed as follows to enable it:.
LVM supports the use of fast block devices such as an SSD device as write-back or write-through caches for large slower block devices. The cache logical volume type uses a small and fast LV to improve the performance of a large and slow LV. To set up LVM caching, you need to create two logical volumes on the caching device. A large one is used for the caching itself, a smaller volume is used to store the caching metadata. These two volumes need to be part of the same volume group as the original volume.
When these volumes are created, they need to be converted into a cache pool which needs to be attached to the original volume:. Add the physical volume from a fast device to the same volume group the original volume is part of and create the cache data volume on the physical volume. Create the cache metadata volume. A tag is an unordered keyword or term assigned to the metadata of a storage object. Tagging allows you to classify collections of LVM storage objects in ways that you find useful by attaching an unordered list of tags to their metadata.
After you tag the LVM2 storage objects, you can use the tags in commands to accomplish the following tasks:. Select LVM objects for processing according to the presence or absence of specific tags. Use tags in the configuration file to control which volume groups and logical volumes are activated on a server.
Replacing the object name with a tag is not supported everywhere yet. After the arguments are expanded, duplicate arguments in a list are resolved by removing the duplicate arguments, and retaining the first instance of each argument. Wherever there might be ambiguity of argument type, you must prefix a tag with the commercial at sign character, such as mytag.
The word cannot begin with a hyphen. The maximum length is characters. You can tag LVM2 physical volumes, volume groups, logical volumes, and logical volume segments. Deleting a volume group also deletes the tags in the orphaned physical volume. Snapshots cannot be tagged, but their origin can be tagged. Add a tag to or tag an LVM2 storage object.
Remove a tag from or untag an LVM2 storage object. Specify the tag to use to narrow the list of volume groups or logical volumes to be activated or deactivated.
Enter the following to activate the volume if it has a tag that matches the tag provided example :. See Section 5. Replace database with your tag. A volume group or logical volume is activated only if a metadata tag matches. The default if there is no match, is not to activate.
When it searches for a specific configuration file entry, it searches the host tag file first, then the lvm. This allows the file for the last tag set to be searched first. New tags set in the host tag file will trigger additional configuration file loads.
Use the same file on every machine in a cluster so that it is a global setting. On the db1 server, enter the following to activate it:. Activate volume group vg1 only on the database hosts db1 and db2. Activate volume group vg2 only on the file server host fs1. Activate nothing initially on the file server backup host fsb1 , but be prepared for it to take over from the file server host fs1. In the following solution, the single configuration file is replicated among multiple hosts.
Add the database tag to the metadata of volume group vg1. In a terminal console, enter. Add the fileserver tag to the metadata of volume group vg2. If the file server host goes down, vg2 can be brought up on fsb1 by entering the following commands in a terminal console on any node:. In the following solution, each host holds locally the information about which classes of volume to activate. On host db1 , create an activation configuration file for the database host db1.
On host db2 , create an activation configuration file for the database host db2. On host fs1, create an activation configuration file for the file server host fs1.
If the file server host fs1 goes down, to bring up a spare file server host fsb1 as a file server:. On host fsb1 , create an activation configuration file for the host fsb1.
Contents Contents. Several hard disks or partitions can be combined in a large logical volume. Launch YaST and open the Partitioner. Warning: Physical Volumes on Unpartitioned Disks You can use an unpartitioned disk as a physical volume PV if that disk is not the one where the operating system is installed and from which it boots. Procedure 5. Thin pool The logical volume is a pool of space that is reserved for use with thin volumes.
Thin volume The volume is created as a sparse volume. Important: Thinly Provisioned Volumes in a Cluster To use thinly provisioned volumes in a cluster, the thin pool and the thin volumes that use it must be managed in a single cluster resource. Mirror images can be temporarily split from the array and then merged back. The array can handle transient failures. Each logical volume is first checked against this list. If it does not match, the logical volume will not be activated. Warning: Data Loss Deleting a volume group destroys all of the data in each of its member partitions.
LVM Commands. Open a terminal console.
0コメント