Linux

 Q:1 Why LVM is required ?

Ans: LVM stands for Logical Volume Manager , to resize filesystem’s size online we required LVM partition in Linux. Size of LVM partition can be extended and reduced using the lvextend & lvreduce commands respectively.

Q:2 How To check Memory stats and CPU stats ?

Ans:  Using ‘free’ & ‘vmstat’ command we can display the physical and virtual memory statistics respectively.With the help of ‘sar’ command we see the CPU utilization & other stats.

Q:3 What does Sar provides and at which location Sar logs are stored ?

Ans: Sar Collect, report, or save system activity information. The default version of the sar command (CPU utilization report) might be one of the first facilities the  user  runs  to  begin system  activity investigation, because it monitors major system resources. If CPU utilization is near 100 percent (user + nice + system), the workload sampled is CPU-bound.

By  default log files of Sar command  is located at  /var/log/sa/sadd file, where the dd parameter indicates the current day.

Q:4 How to increase the size of LVM partition ?

Ans: Below are the Logical Steps :

– Use the lvextend command (lvextend -L +100M /dev/<Name of the LVM Partition> , in this example we are extending the size by 100MB.

– resize2fs /dev/<Name of the LVM Partition>

– check the size of partition using ‘df -h’ command

Q:5 How to reduce or shrink the size of LVM partition ?

Ans: Below are the logical Steps to reduce size of LVM partition :

-Umount the filesystem using umount command,

-use resize2fs command , e.g resiz2fs /dev/mapper/myvg-mylv 10G

-Now use the lvreduce command , e.g lvreduce -L 10G /dev/mapper/myvg-mylv

Above Command will shrink the size & will make the filesystem size 10GB.

 Q:6 How to create partition from the raw disk ?

Ans: Using fdisk utility we can create partitions from the raw disk.Below are the steps to create partition from the raw dsik :

– fdisk  /dev/hd* (IDE) or /dev/sd* (SCSI)

– Type n to create a new partition

–  After...