How to use PowerPath pseudo-devices with existing devices.

now that you have PowerPath installed, even though you are using native devices ..PowerPath is so low in the stack that it automatically load-balances. Do you really need to have emcpowerX devices in the volume group ?

Hello,

I'm not using LVM with these volumes.

Yes, I need to use the PowerPath's pseudo-devices.

# fdisk -l

Disk /dev/sdb: 10.7 GB, 10737418240 bytes

64 heads, 32 sectors/track, 10240 cylinders

Units = cylinders of 2048 * 512 = 1048576 bytes

Device Boot      Start         End      Blocks   Id  System

/dev/sdb1               1       10240    10485744   83  Linux

Disk /dev/sdc: 10.7 GB, 10737418240 bytes

64 heads, 32 sectors/track, 10240 cylinders

Units = cylinders of 2048 * 512 = 1048576 bytes

Device Boot      Start         End      Blocks   Id  System

/dev/sdc1               1       10240    10485744   83  Linux

# cat /proc/partitions

major minor  #blocks  name

8     0  143153152 sda

8     1     102384 sda1

8     2  143050752 sda2

8    16   10485760 sdb

8    17   10485744 sdb1

8    32   10485760 sdc

8    33   10485744 sdc1

8    48   10485760 sdd

8    49   10485744 sdd1

8    64   10485760 sde

8    65   10485744 sde1

253     0  141000704 dm-0

253     1    2031616 dm-1

120     0   10485760 emcpowera

120     1   10485744 emcpowera1

120    16   10485760 emcpowerb

120    17   10485744 emcpowerb1

# powermt display dev=all

Pseudo name=emcpowerb

CLARiiON ID=XXX [SG_XYZ]

Logical device ID=600601606A400F008ABBF1D2D794DF11 [LUN 11]

state=alive; policy=CLAROpt; priority=0; queued-IOs=0

Owner: default=SP A, current=SP A       Array failover mode: 1

==============================================================================

---------------- Host ---------------   - Stor -   -- I/O Path -  -- Stats ---

###  HW Path                I/O Paths    Interf.   Mode    State  Q-IOs Errors

==============================================================================

2 lpfc                      sdc       SP A0     active  alive      0      0

2 lpfc                      sde       SP B1     active  alive      0      0

Pseudo name=emcpowera

CLARiiON ID=XXX [SG_XYZ]

Logical device ID=600601606A400F008BBBF1D2D794DF11 [LUN 12]

state=alive; policy=CLAROpt; priority=0; queued-IOs=0

Owner: default=SP A, current=SP A       Array failover mode: 1

==============================================================================

---------------- Host ---------------   - Stor -   -- I/O Path -  -- Stats ---

###  HW Path                I/O Paths    Interf.   Mode    State  Q-IOs Errors

==============================================================================

2 lpfc                      sdb       SP A0     active  alive      0      0

2 lpfc                      sdd       SP B1     active  alive      0      0

I would like to use the partition emcpowera1 without to loose the contents of the partition sdb1.

On /etc/fstab:

...

/dev/sbd1              /usr2        ext3        defaults        0        3

I would like on /etc/fstab:

....

/dev/emcpowera1        /usr2        ext3        defaults        0        3

Any ideas, please?

Regards.

i would try to mount it manually before you put it in fstab. It's either going to mount or not ..it should not affect data residing on the drive. Unmount native device and try it with emcpowera1

It is common to use LVM in Linux and so thiking what is the need of using device files(either native or emcpower) in fstab rather it would be like /dev/vgname/lvname. In case you don't use LVM then go with emcpower devices in fstab, u can specify even each paritions on the emcpower devices. Also label the paritions so that in case any time the emcpower device file changes, u can track with labels easily.