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Creating logical volumes and viewing and modifying attributes for AIX storage management

2022-07-02 00:40:00 【51CTO】

restudy old materials ：

In the last article 《AIX View and modify the volume group properties of storage management （ Two ）》 Talked about it. AIX How to view and modify the properties of a volume group . I won't repeat them here , Just a point ： If there is someone unfamiliar with the command , have access to smit Tools to operate .

Link to the original text ： AIX View and modify the volume group properties of storage management （ Two ）

know sth. new ：

Today we will talk about viewing and modifying the properties of logical volumes , After talking about logical volumes , About AIX Storage management is basically over . A summary will be made later , You can have a look if you are interested .

One 、 Create logical volumes

That is, how to create a logical volume . There are also several points to pay attention to when creating logical volumes ：

How many logical partitions does the logical volume contain , That is, specify the size of the logical volume ;
In which volume group are logical volumes created , Indicates the volume group name to which the logical volume belongs ;
Indicates the name of the logical volume ;
Indicate on which physical volume to create the logical volume ;
Indicate where the physical partition assigned to the logical volume is located on the physical volume , That is, the internal disk allocation policy ;
Whether to mirror the logical volume , There are several copies ;
If you mirror a logical volume , The distribution strategy of the physical partition of each replica on the physical volume should be pointed out , That is, the allocation strategy between disks ;
Whether to open the write validation of the logical volume .

The command used to create a logical volume is mklv , for instance ： stay rootvg Created in gaolv. The logical volume is mirrored with two copies , share 20 Logical partitions , Each logical partition maps to two physical partitions , Then the physical partition is 40 individual .

      
      
       
       mklv -y gaolv -c 2 rootvg 20
      
      
      
      
       
       1.

It can also be used smit Tools , The command used is ：

      
      
       
       smitty lv
       
       
 Enter the interface tool 
      
      
      
      
       
       1.
       
       2.

1、 Select Add logical volume

AIX Create logical volumes for storage management and view and modify attributes _ data

2、 Fill logical volume The name of the volume group to which it belongs

AIX Create logical volumes for storage management and view and modify attributes _ Logic volume _02

3、 Fill in the properties of the logical volume

AIX Create logical volumes for storage management and view and modify attributes _AIX_03

Fill in the corresponding information .

There's a little problem . Do you know how to calculate the size of the logical volume in the actual physical hard disk ？ Through the previous explanation , It is not difficult to know that logical volumes are composed of logical partitions , So just know how many logical partitions there are . Is that right ？？？ This statement is half right , The reason is that a logical partition can map one to three physical partitions .

1、 If the logical volume has no copies （ Namely Lv Its own size ）

The size of the logical volume in the actual physical hard disk （MB）=PP Size （MB）×LV contain LP The number of

2、 If the logical volume has a copy

The size of the logical volume in the actual physical hard disk （MB）= PP Size （MB）×LV contain LP Count （ individual ）×LV Number of copies

One more little question ： Do you know how to change the size of a logical volume ？ By adding and reducing logical partitions , You can change the size of a logical volume ; By increasing and decreasing the number of mirrors of logical volumes , You can change the physical location of the logical volume on the disk .

Two 、 View logical volume properties

1、 Displays all logical volumes in a volume group

      
      
       
       lsvg -l rootvg
      
      
      
      
       
       1.

AIX Create logical volumes for storage management and view and modify attributes _LV_04

2、 Displays the detailed properties of the logical volume

AIX Create logical volumes for storage management and view and modify attributes _ data _05

3、 Displays the physical volume spanned by a logical volume and the distribution of the logical volume on the physical volume

      
      
       
       lslv -l gaolv
      
      
      
      
       
       1.

AIX Create logical volumes for storage management and view and modify attributes _LV_06

Be careful ：

"COPIES" The list shows that the logical volume is on the same physical volume 3 Used in copies PP Count ."COPIES" The format description of the column is shown in Figure :

AIX Create logical volumes for storage management and view and modify attributes _ data _07

If the logical volume gaolv Two copies of are on the same physical volume hdisk1 On , be hdisk1 Corresponding "COPIES" The contents of the column should be ∶ 128∶128∶000, Such logical volume mirroring cannot be avoided hdisk1 Single point of failure of physical volumes , When hdisk1 There is a problem with the hard disk , Then the whole gaolv Will lose .
"DISTRIBUTION" The contents of the column represent the contents of the logical volume PP Distribution on physical volumes .

AIX Create logical volumes for storage management and view and modify attributes _ Logic volume _08

The following is an example ：gaolv Logical volume in hdisk1 There are 64 individual PP At the outer and inner edges , stay hdisk0 There are 32 individual PP Located on the outer edge ,96 individual PP Located on the inner edge .

AIX Create logical volumes for storage management and view and modify attributes _LV_06

4、 Displays the logical volume allocation on the specified physical volume

      
      
       
       lslv -p hdisk0
      
      
      
      
       
       1.

AIX Create logical volumes for storage management and view and modify attributes _ Logic volume _10

5、 Displays the replica allocation of the mirrored logical volume

      
      
       
       lslv -m gaolv
      
      
      
      
       
       1.

AIX Create logical volumes for storage management and view and modify attributes _ Logic volume _11

3、 ... and 、 Logical volume attribute modification

If you want to modify the properties of a logical volume , It is recommended to use smit Tools , Because for me personally , You need to remember a lot of parameters when using commands to modify attributes , My brain is not easy to use .

      
      
       
       smitty chlv
      
      
      
      
       
       1.

1、 Select Modify logical volume

AIX Create logical volumes for storage management and view and modify attributes _ Operation and maintenance _12

2、 Fill in the logical volume name

AIX Create logical volumes for storage management and view and modify attributes _ Logic volume _13

3、 Enter the modify interface

AIX Create logical volumes for storage management and view and modify attributes _ Logic volume _14

Four 、 Copy logical volumes

1、 Copy a logical volume to a new logical volume .

      
      
       
       cplv -γ rootvg -y newlv oldlv
      
      
      
      
       
       1.

This command will delete the old logical volume oldlv Copy the contents of to a new logical volume newlv On , The new logical volume is named myvg In the volume group of . If you do not specify a volume group , The new logical volume is in the same volume group as the old logical volume .
cplv The command will not start with a logical volume 512 Copy bytes to the new logical volume , Because of this 512 Bytes are LVCB, But it will write new logical volumes with new attributes LVCB.

2、 Copy a logical volume to an existing logical volume .

      
      
       
       # cplv-e existinglv oldlv
      
      
      
      
       
       1.

This command will delete the old logical volume oldlv Copy the contents of to an existing logical volume , Both logical volumes are in the same volume group . Because you want to overwrite data that already exists on the logical volume , Therefore, the user is required to confirm whether to continue the copy operation . If the existing logical volume is smaller than the old logical volume , You may lose data , And cause the copy operation to fail .

It can also be used smit Tools to operate , Carry out orders ：

1、 Select the deepened part in the figure

AIX Create logical volumes for storage management and view and modify attributes _ Operation and maintenance _15

2、 Just choose the corresponding way

AIX Create logical volumes for storage management and view and modify attributes _LV_16

The first is to copy to an existing logical volume , The second is to copy to the user created logical volume , The third is to copy to the logical volume created by the system .

5、 ... and 、 Logical volume increase / Reduce copies

Use smit Tools , Carry out orders

1、 Select the deepened part

AIX Create logical volumes for storage management and view and modify attributes _ Operation and maintenance _17

2、 Select Article 3 or 4 to add or delete copies

AIX Create logical volumes for storage management and view and modify attributes _AIX_18

expand ：

Have you ever thought about what factors are affecting the performance of logical volumes . Here I will briefly talk about two factors . One is the internal allocation of the disk , The second is the allocation between disks .

Internal disk allocation refers to the physical partition of the logical volume stored in the actual location of the disk . For a single disk only , For frequently used 、 The most frequently accessed logical volumes are recommended to be placed in the central area of the disk , For logical volumes that do not need frequent access, it is recommended to put them at the edge . But there is a special case ： On the outer edge of the disk （Outer-Edge） More data blocks are stored on each track of the disk than on each track in other areas of the disk , therefore , For applications that need to perform a large number of sequential read and write operations , If you store data on the outer edge of the disk , It will produce higher throughput .

Allocation between disks refers to the distribution of physical partitions of logical volumes on multiple physical volumes . In the same volume group , The physical partitions of a specified logical volume can be distributed on one or more disks , This is done by creating the logical volume "RANGE of physical volumes" Setting of options （ In use smitty mklv Command to create LV when ） To decide . This option （ namely Range） There are two range values ∶ minimum（ Minimum number ） and maximum（ The maximum number ）.
1）minimum Physically and logically represent a volume , If one physical volume is not enough , Then put the physical partition on as few physical volumes as possible .minimum Value can only be used to increase the availability of data , Instead of setting logical volumes that require frequent access minimum value .
2）maximum It means that the physical partitions of the logical volume are distributed on as many physical volumes as possible , It is usually distributed on all physical volumes in the volume group as much as possible .maximum Value can reduce the average time to access logical volumes . If a non mirrored logical volume spans multiple physical volumes , Then the error of any physical volume will lead to the loss of data , Make the data of the logical volume incomplete .maximum Value is a performance oriented setting , It should be used in conjunction with mirroring to improve data availability and logical volume performance .

Let's stop here for the moment about logical volumes , The next article brings you 《 AIX Summary of storage management 》

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