Paths for vscsi disks unable to open on VIO Client LPARs after SDDPCM 2.6.3.2 upgrade along with HostAttach 1.0.0.23 on VIO Servers

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Abstract

After upgrading sddpcm to 2.6.3.2 on VIO Server, vscsi disk paths become unavailable on VIO Client and rescan will not open them. SDDPCM and AIX see all the disks as open and available on VIO Servers. However, there is an issue with exporting these disks to VIO Client lpars, all the paths to vscsi disks from the VIOS are showing up as failed.

Content

A change was made in host attachment 1.0.0.23, which modified the default max_transfer value for many IBM disk types from 0x100000 to 0x40000. The change results in a mismatch between max_transfer values of vhost device of VIO Server and vscsi device on VIO Client LPARs, causing vscsi disk paths to result in a failed state and unable to open.
Workaround

If you are unable to upgrade, a work around is provided to modify the max_transfer value using ODM commands to be used with caution:.

Otherwise, if you are able to perform an upgrade of the host attachment, you should refer to the Recommend Fix section following the workaround

--Create this file and save as /tmp/odm.add------------------
PdAt:
uniquetype = "disk/fcp/2107"
attribute = "max_transfer"
deflt = "0x100000"
values = "0x20000,0x40000,0x80000,0x100000,0x200000,0x400000,0x800000,0x1000000"
width = ""
type = "R"
generic = "DU"
rep = "nl"
nls_index = 87
------------------------------------------------------------------------

odmget -q "attribute=max_transfer AND uniquetype=disk/fcp/2107" PdAt
odmdelete -o PdAt -q "attribute=max_transfer AND uniquetype=disk/fcp/2107"
odmadd /tmp/odm.add

odmget -q "attribute=max_transfer AND uniquetype=disk/fcp/2107" PdAt


Before Modifying ODM

PdAt:
uniquetype = "disk/fcp/2107"
attribute = "max_transfer"
deflt = "0x40000"
values = "0x20000,0x40000,0x80000,0x100000,0x200000,0x400000,0x800000,0x1000000"
width = ""
type = "R"
generic = "DU"
rep = "nl"
nls_index = 87

After modifying ODM.

PdAt:
uniquetype = "disk/fcp/2107"
attribute = "max_transfer"
deflt = "0x100000"
values = "0x20000,0x40000,0x80000,0x100000,0x200000,0x400000,0x800000,0x1000000"
width = ""
type = "R"
generic = "DU"
rep = "nl"
nls_index = 87

Recommended Fix:

Download and install the 1.0.0.24 version of Host Attachment

Refer to the SDD User's Guide for installation instruction regarding host attachment

NOTE: Only IBM 2107 disk type were used in these instructions. If the max_transfer value is changed for other disk types also, then they will need to be modified using the procedure above as well.


Cross reference information
Segment Product Component Platform Version Edition
Operating System (AIX) AIX Enterprise Edition AIX 6.1

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Document information


More support for:

Host Attachment Scripts

Software version:

2.7.1.00

Operating system(s):

AIX

Software edition:

N/A

Reference #:

S1004304

Modified date:

2014-02-20

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