Steps for online raid resizing on the DELL server Centos

Source: Internet
Author: User
Tags dell r710
I. CentOS6.2 configuring LVMLVM is short for logical disk volume management (LogicalVolumeManager). It is a mechanism for managing disk partitions in Linux, LVM is a logical layer built on hard disks and partitions to improve the flexibility of disk partition management. The operating principle of LVM is actually very simple. it is to configure LVM by abstracting the underlying physical hard disk block 1 and CentOS6.2.

LVM is short for Logical Volume Manager. it is a mechanism for managing disk partitions in Linux, LVM is a logical layer built on hard disks and partitions to improve the flexibility of disk partition management.
The operating principle of LVM is actually very simple. it encapsulates the underlying physical hard disk abstraction and presents it to upper-layer applications in the form of logical volumes. In the traditional disk management mechanism, our upper-layer applications directly access the file system to read the underlying physical hard disk. in LVM, it encapsulates the underlying hard disk. when we operate the underlying physical hard disk, it is no longer for partitioning, instead, you can manage the underlying disk of a logical volume. For example, if I add a physical hard disk, the upper-layer service will not feel it at this time, because the upper-layer service is presented in a logical volume.
The biggest feature of LVM is its ability to dynamically manage disks. Because the logical volume size can be dynamically adjusted without losing existing data. If we add a new hard disk, it will not change the existing upper-layer logical volume. As a dynamic disk management mechanism, logical volume technology greatly improves the flexibility of disk management.
Basic logical volume management concepts:
PV (Physical Volume)-Physical Volume
The physical volume is at the bottom of the logical volume management. it can be a partition on the actual physical hard disk, an entire physical hard disk, or a raid device.
VG (Volumne Group)-Volume Group
A volume is created on top of a physical volume. a volume group must contain at least one physical volume. after a volume group is created, the physical volume can be dynamically added to the volume group. A logical volume management system project can have only one or more volume groups.
LV (Logical Volume)-Logical Volume

The logical volume is created on the volume group. unallocated space in the volume group can be used to create new logical volumes. after the logical volume is created, the space can be dynamically expanded and reduced. Multiple logical volumes in the system can belong to the same volume group or different volume groups.
The diagram is as follows:

PE (Physical Extent)-Physical block
LVM uses a 4 mb pe block by default, while LVM's LV can contain up to 65534 PES (lvm1 format ), therefore, the maximum LV capacity of the default LVM is 4 M * 65534/(1024 M/G) = 256G. PE is the smallest storage block of the entire LVM. that is to say, our data is written into PE for processing. Simply put, this PE is a bit like the block size in the file system. So adjusting PE will affect the maximum capacity of LVM! However, after CentOS 6.x, this restriction does not exist because lvm2 format functions are directly used.

As LVM can dynamically manage disks, we adopt standard partitions for system disks and LVM partitions for raid5 and raid0 when installing CentOS to facilitate dynamic resizing later.

Create a PV --> Create a VG (including the created PV). you can create a PV after installing the system, as shown in:


II. OMSA online RAID resizing

For OMSA installation instructions, see Dell PowerEdge R710 install OpenManage Server Administrator in Red Hat 6.2.
After the service is successfully installed, open the management page, select the Virtual Disk to be resized, select Reconfigure, and execute

Add a new hard disk to the RAID to continue (if there are multiple RAID, please note that select the connector 0-N) select the raid level, continue to use Progress to view the expansion Progress after the expansion is successful, restart the server. 3. after CentOS6.2 adds a capacity for the partition and the server is restarted, log on to the root user and run the fdisk-l command to view the current partition capacity. the output result shows that the sdb has been expanded, but the/dev/mapper/VolGroup-LogVol00 has not been resized successfully. Start partitioning (note: LVM is required). now you can use fdisk-l to check whether the original partition has not changed. it will be automatically loaded after restart. Log on to the root user and check that the sdb2 partition already exists. Format sdb2 to create a physical volume --> add the created PV to the volume group --> view the volume group --> increase the var partition by 930 GB and run the command to check whether the file system uses fdisk-l to view it, the df-lh command is used to check whether the Mount directory or var file is successfully resized. the steps for online raid resizing on the DELL R710 server Centos6.2 are complete. We hope this will help you make better progress.
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