Archives for March 2022

pstree command is used to display the parent-child relationship in a hierarchical format. The output of this command is quite similar to the output of the ‘ps axjf’ command and the ‘ps -ef –forest’ command, as shown in the following command line: $ pstree The following screenshot displays the tree hierarchy of a single process […]

pvchange command changes allocation permissions on a physical volume. You might disallow new allocations if you’re making changes on other volumes and intend to delete one immediately thereafter. The UUID of PV can be re-generated with the command pvchange. For example: # pvchange –uuid [pv-name] Please make sure to deactivate the VG in question vgchange […]

pvck command checks the physical volume for errors; similar to fsck for filesystems. Syntax: # pvck [options] pvck Command Examples 1. To scan the physical volume metadata: # pvck PhysicalVolume /dev/sda2 2. To specify the starting sector from where it should scan: # pvck –labelsector sector 3. To debug the physical volume metadata: # pvck […]

The first step in creating an LVM is to take existing physical devices and convert them into physical volumes (PVs). This is accomplished by executing the pvcreate command. For example, if you have a hard drive partition /dev/sdb2 and you want to make it a PV, you can execute the following command: # pvcreate /dev/sdb2 […]

You can use the pvdisplay command to display a list of physical volumes you’ve created if you’d like to see your progress along the way: # pvdisplay /dev/sdb1 “/dev/sdb1” is a new physical volume of “2.01 GiB” — NEW Physical volume — PV Name /dev/sdb1 VG Name PV Size 2.01 GiB Allocatable NO PE Size […]

pvmove should be used to move the physical volume extents from the old SAN to the new SAN. It is a common misconception that migrations of this sort should be done by manually creating and manipulating mirrors. This is incorrect and exposes one to risk. pvmove was designed to facilitate this functionality and is much […]

The permissions bits applied to a file system object correspond directly to the values which can be specified in the 4 digit tuple supplied to the chmod utility in the following command: # chmod abcd [file system object] Each value in the digit set abcd is made up of a sum of the values 1 […]

To display the LVM physical volume on a system, you can use either the pvs command or the pvscan command as the root user. For example, the below commands create a physical volume on /dev/sdc1 partition and views the information about it in the next pvs command. $ sudo pvcreate /dev/sdc1 ### Make sdc1 an […]

To display the LVM physical volume on a system, you can use either the pvs command or the pvscan command as the root user. The output of sudo pvscan is shown in the following screenshot: To implement LVMs, we create three objects: Physical volumes: This represents the raw disk space as disk partitions. When we […]

repquota is used to report on the status of quotas. In the first form, repquota displays a summary report on the quotas for the given filesystems on a per-user or per-group basis. In the second form, the -a option causes a summary for all filesystems with quotas to be displayed. This command fails for nonroot […]