Logical Volume in Linux : Interview Questions

Logical Volume in LVM: Interview Questions

Display:

#lvdisplay -v lvname

#lvs

To view mirror volumes

#lvs -a -o +devices
#lvs -a -o +seg_pe_ranges --segments

lvs attributes are:

1. volume type: (m)irrored, (M)irrored without initail sync, (o)rigin, (p)vmove, (s)napshot, invalid (S)napshot, (v)irtual, mirror (i)mage
                      mirror (I)mage out-of-sync, under (c)onversion
2. permissions: (w)rite, (r)ead-only
3. allocation policy - (c)ontiguous, c(l)ing, (n)ormal, (a)nywhere, (i)nherited
4. fixed (m)inor
5. state: (a)ctive, (s)uspended, (I)nvalid snapshot, invalid (S)uspended snapshot, mapped (d)evice present with-out tables,
             mapped device present with (i)nactive table
6. device (o)pen (mounted in other words) 

Scan: 

#lvscan -v
#lvmdiskscan



Create / Extend / Reduce / Remove:

Create a Lvol

#lvcreate -L 10M -n lvol1 VGNAME  // To create plain lvol

#lvcreate -i 3 -I 32 -L 24M -n lvol1 vg01  //To create striped lvol

#lvcreate -L 10M -m1 -n lvol1 vg01  // To Create mirror lvol

Extend a Lvol 

#lvextend -L 20M /dev/VolData00/lvol01 

#fsadm resize /dev/VolData01/data01
#resize2fs -p /dev/mapper/VolData01-data01 [size] 

Reduce Lvol

#lvreduce -L 5M /dev/VolData00/lvol01 (or)
#lvresize -L 5M /dev/VolData00/lvol01

#fsadm resize /dev/VolData01/data01 [size]
#resize2fs -p /dev/mapper/VolData01-data01 [size] 


Rename / Snapshot / change attribute 


# lvrename /dev/VolData00/vol_old /dev/VolData00/vol_new    //Rename

# lvcreate --size 100M --snapshot -name snap /dev/vg01/data01    //Snapshot

#lvchange -a n /dev/VolData00/vol01   //Changing attribute