How to set PV alternative path

[prajul.keeriyat]

Hi,

I need to set alternative path to all my Pv's,could you please help me on this,

OS - HP-UX 11.11v

Thanks in Adv.

[Mel Burslan]

For the sake of easy explanation, let's assume your volumes are on a SAN and lets say, one LUN has 4 paths coming to it, as follows:

/dev/dsk/c1t2d0
/dev/dsk/c2t2d0
/dev/dsk/c3t2d0
/dev/dsk/c4t2d0

and your VG is created only on the first device, i.e., /dev/dsk/c1t2d0

all you need to do is add the remaining paths to your VG with vgextend command, as such:

vgextend vgXX /dev/dsk/c2t2d0
vgextend vgXX /dev/dsk/c3t2d0
vgextend vgXX /dev/dsk/c4t2d0

you do not need to (actually you must not) run pvcreate command on this additional paths as it will destroy your existing LVM data recorded on this particular LUN.

On the other hand, this method by no means an intelligent multi-pathing solution. Depending on which SAN hardware (HP, EMC, etc) and which multi-path software (More than likely SecurePath or PowerPath) you are using, you need to refer to their respective documentation and man pages to set up multi-path, according to the needs of your infrastructure.

Hope this helps.

[Shibin_2]

All you have to do is, find out what are the alternate paths of existing disks.

Use ioscan -fnC disk to find this.

If you are using XP disks, then you can use a utility called xpinfo ( if installed, check with your storage admin ).


E.g. you have disk /dev/dsk/c12t1d2 . Alternate paths of this disks will be cxt1d2. It changes only the controller number.

Once you collected these, do vgextend.

If you have 3 alternate path for your existing disk,

vgextend /dev/dsk/cxt1d2 /dev/dsk/cyt1d2 /dev/dsk/czt1d2

where x, y and z are controller number.

[Deepak Kr]

Like other people mentioned, you need to collec t details about the alternate device links using ioscan and xpinf/evainfo etc.

Can you paste following output:

#ioscan -fnC disk

[prajul.keeriyat]

Please find the #ioscan -fnC disk output.

# ioscan -fnC disk
Class I H/W Path Driver S/W State H/W Type Description
==========================================================================
disk 0 0/0/3/0.0.0.0 sdisk CLAIMED DEVICE TEAC DW-224E-B
/dev/dsk/c0t0d0 /dev/rdsk/c0t0d0
disk 1 0/1/1/0.0.0 sdisk CLAIMED DEVICE HP 73.4GST373453LC
/dev/dsk/c2t0d0 /dev/rdsk/c2t0d0
disk 2 0/1/1/0.1.0 sdisk CLAIMED DEVICE HP 73.4GST373453LC
/dev/dsk/c2t1d0 /dev/rdsk/c2t1d0
disk 29 0/2/1/0.1.0.0.0.0.0 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t0d0 /dev/rdsk/c10t0d0
disk 35 0/2/1/0.1.0.0.0.0.1 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t0d1 /dev/rdsk/c10t0d1
disk 36 0/2/1/0.1.0.0.0.0.2 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t0d2 /dev/rdsk/c10t0d2
disk 37 0/2/1/0.1.0.0.0.0.3 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t0d3 /dev/rdsk/c10t0d3
disk 38 0/2/1/0.1.0.0.0.0.4 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t0d4 /dev/rdsk/c10t0d4
disk 43 0/2/1/0.1.0.0.0.0.5 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t0d5 /dev/rdsk/c10t0d5
disk 44 0/2/1/0.1.0.0.0.0.6 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t0d6 /dev/rdsk/c10t0d6
disk 45 0/2/1/0.1.0.0.0.0.7 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t0d7 /dev/rdsk/c10t0d7
disk 46 0/2/1/0.1.0.0.0.1.0 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t1d0 /dev/rdsk/c10t1d0
disk 51 0/2/1/0.1.0.0.0.1.1 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t1d1 /dev/rdsk/c10t1d1
disk 52 0/2/1/0.1.0.0.0.1.2 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t1d2 /dev/rdsk/c10t1d2
disk 53 0/2/1/0.1.0.0.0.1.3 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t1d3 /dev/rdsk/c10t1d3
disk 54 0/2/1/0.1.0.0.0.1.4 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c10t1d4 /dev/rdsk/c10t1d4
disk 56 0/2/1/0.1.0.0.0.1.5 sdisk NO_HW DEVICE DGC CX4-480WDR5
/dev/dsk/c10t1d5 /dev/rdsk/c10t1d5
disk 30 0/2/1/0.1.1.0.0.0.0 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t0d0 /dev/rdsk/c12t0d0
disk 31 0/2/1/0.1.1.0.0.0.1 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t0d1 /dev/rdsk/c12t0d1
disk 32 0/2/1/0.1.1.0.0.0.2 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t0d2 /dev/rdsk/c12t0d2
disk 33 0/2/1/0.1.1.0.0.0.3 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t0d3 /dev/rdsk/c12t0d3
disk 34 0/2/1/0.1.1.0.0.0.4 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t0d4 /dev/rdsk/c12t0d4
disk 39 0/2/1/0.1.1.0.0.0.5 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t0d5 /dev/rdsk/c12t0d5
disk 40 0/2/1/0.1.1.0.0.0.6 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t0d6 /dev/rdsk/c12t0d6
disk 41 0/2/1/0.1.1.0.0.0.7 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t0d7 /dev/rdsk/c12t0d7
disk 42 0/2/1/0.1.1.0.0.1.0 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t1d0 /dev/rdsk/c12t1d0
disk 47 0/2/1/0.1.1.0.0.1.1 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t1d1 /dev/rdsk/c12t1d1
disk 48 0/2/1/0.1.1.0.0.1.2 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t1d2 /dev/rdsk/c12t1d2
disk 49 0/2/1/0.1.1.0.0.1.3 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t1d3 /dev/rdsk/c12t1d3
disk 50 0/2/1/0.1.1.0.0.1.4 sdisk CLAIMED DEVICE DGC CX4-480WDR5
/dev/dsk/c12t1d4 /dev/rdsk/c12t1d4
disk 55 0/2/1/0.1.1.0.0.1.5 sdisk NO_HW DEVICE DGC CX4-480WDR5
/dev/dsk/c12t1d5 /dev/rdsk/c12t1d5
disk 20 0/5/2/0.8.0.1.0.0.0 sdisk CLAIMED DEVICE COMPAQ MSA1000 VOLUME
/dev/dsk/c6t0d0 /dev/rdsk/c6t0d0
disk 26 0/5/2/0.8.0.1.0.0.6 sdisk CLAIMED DEVICE COMPAQ MSA1000 VOLUME
/dev/dsk/c6t0d6 /dev/rdsk/c6t0d6
disk 27 0/5/2/0.8.0.1.0.0.7 sdisk CLAIMED DEVICE COMPAQ MSA1000 VOLUME
/dev/dsk/c6t0d7 /dev/rdsk/c6t0d7
disk 28 0/5/2/0.8.0.1.0.1.0 sdisk CLAIMED DEVICE COMPAQ MSA1000 VOLUME
/dev/dsk/c6t1d0 /dev/rdsk/c6t1d0

[prajul.keeriyat]

Storage - CX4-480WDR5 and MSA1000

[Torsten.]

Looks like the MSA has only a single path to the server. The other array is probably double connected to the switch, but there is a single connection between switch and server.

Can you confirm?

[prajul.keeriyat]

What is the path of powermnt?