Identify a striped LV

zdenisl · 06-18-2007, 01:19 PM

I can't find a way to verify if a LV is striped.
Is there a command which will show me if striping is enabled for a LV?

Thanks.

jlg3 · 06-18-2007, 01:35 PM

cat /proc/mdstat does it for me.

Code:

[root@qpak mnt]# cat /proc/mdstat
Personalities : [raid0] [raid1]
md0 : active raid0 hdb1[1] hda2[0]
      154207744 blocks 256k chunks

md1 : active raid1 sda1[0] sdb1[1]
      104320 blocks [2/2] [UU]

md2 : active raid1 sda2[0] sdb2[1]
      156183808 blocks [2/2] [UU]

unused devices: <none>

This shows a RAID 0 array (striped) using 2 IDE hard drives and two RAID 1 arrays (mirror) using 2 SATA drives.

If you want to dig further then fdisk -l will show how the drives are partitioned:

Code:

[root@qpak mnt]# fdisk -l /dev/hda

Disk /dev/hda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1          13      104391   83  Linux
/dev/hda2              14        9612    77103967+  fd  Linux raid autodetect
[root@qpak mnt]# fdisk -l /dev/hdb

Disk /dev/hdb: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdb1   *           1        9599    77103936   fd  Linux raid autodetect
/dev/hdb2            9600        9729     1044225   82  Linux swap
[root@qpak mnt]# fdisk -l /dev/sda

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          13      104391   fd  Linux raid autodetect
/dev/sda2              14       19457   156183930   fd  Linux raid autodetect
[root@qpak mnt]# fdisk -l /dev/sdb

Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1          13      104384+  fd  Linux raid autodetect
Partition 1 does not end on cylinder boundary.
/dev/sdb2              13       19457   156183967   fd  Linux raid autodetect
[root@qpak mnt]#

zdenisl · 06-18-2007, 01:45 PM

I don't see how the above examples show that LVM is striping the data across the pv's.

However, I did just find my answer!

Code:

[root@rhel014 ~]# lvdisplay --maps /dev/stripe_54/stripe_54
  --- Logical volume ---
  LV Name                /dev/stripe_54/stripe_54
  VG Name                stripe_54
  LV UUID                t3Bb9U-yiwM-uLgE-xajs-VoUJ-jngM-ZfJt1X
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                179.94 GB
  Current LE             46064
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:0
   
  --- Segments ---
  Logical extent 0 to 46063:
    Type                striped
    Stripes             4
    Stripe size         4 KB
    Stripe 0:
      Physical volume   /dev/dasdj1
      Physical extents  0 to 11515
    Stripe 1:
      Physical volume   /dev/dasdk1
      Physical extents  0 to 11515
    Stripe 2:
      Physical volume   /dev/dasdl1
      Physical extents  0 to 11515
    Stripe 3:
      Physical volume   /dev/dasdm1
      Physical extents  0 to 11515

The "--map" option.

zdenisl · 06-18-2007, 02:00 PM

Another way...

Code:

[root@rhel014 ~]# lvs --segments
  LV          VG              Attr   #Str Type    SSize   
  stripe_54   stripe_54       -wi-ao    4 striped 179.94G 
  stripe_54-b stripe_54       -wi-ao    4 striped 179.94G 
  tsm-pad5-01 tsm-pad5-nosrdf -wi-ao    1 linear   44.98G 
  tsm-pad5-02 tsm-pad5-nosrdf -wi-ao    1 linear   44.98G 
  tsm-pad5-03 tsm-pad5-nosrdf -wi-ao    1 linear   44.98G 
  mlextras    vg-mlextras     -wi-ao    1 linear    1.02G 
  tivoli      vg1             -wi-ao    1 linear    2.05G

kajio11 · 01-24-2010, 08:23 AM

Thanx alot for the information...

It really helped