SANtricity express configuration manuals ( CA08872-012 )

Learn about Solaris express configuration

The Solaris express method for installing your storage array and accessing SANtricity System Manager is appropriate for setting up a standalone solaris host to an ETERNUS AB/HB series storage system. It is designed to get the storage system up and running as quickly as possible with minimal decision points.

Procedure overview

For more information about solaris express methods, see the Express Configuration For Oracle Solaris documentation.

Application of the Multipath Diagnostic Program

For environments with the Oracle Solaris standard multipath driver (MPxIO), the Multipath Diagnostic Program can be applied.

The Multipath Diagnostic Program performs regular diagnosis on the connection paths between the server and the ETERNUS AX/AC/HX series or ETERNUS AB/HB series, and issues a request to switch the paths if an error is detected.

The following describes the phenomenon and details when an error occurs.

Phenomenon

The Oracle Solaris standard multipath driver (MPxIO) does not switch paths even when a timeout error occurs due to a transmission path failure. Therefore, the system may slow down.

For a cluster system that is configured with PRIMECLUSTER, a system slowdown may cause a failover (node switching due to a panic).

Impact on the Business

The system slowdown may cause a delay in business or a failover (node switching due to a panic).

Environment

The following server environment is used and multipath is configured with MPxIO (*1).

Server	OS
SPARC Enterprise, SPARC Servers	Solaris 11.3, 11.4

Server

SPARC Enterprise, SPARC Servers

Solaris 11.3, 11.4

(*1): To check whether the multipath has been configured with MPxIO, execute the format command and check whether the device path name is displayed with scsi_vhci. If the path names are displayed with scsi_vhci, multipath is configured with MPxIO. However, for PRIMECLUSTER GD, because the path names cannot be checked with the format command, use the luxadm command instead.

(Execution example of the format command)

#format
Searching for disks...done

AVAILABLE DISK SELECTIONS:
 0. c0t0d0 <FUJITSU-MBD2147RC-3701 cyl 14087 alt 2 hd 24 sec 848>
   /pci@0,600000/pci@0/pci@0/scsi@0/sd@0,0
 1. c0t1d0 <FUJITSU-MBD2147RC-3701 cyl 14087 alt 2 hd 24 sec 848>
   /pci@0,600000/pci@0/pci@0/scsi@0/sd@1,0
 2. c3t600000E00D000000000120C500000000d0 <FUJITSU-ETERNUS_AHB-0000-2.13TB>
    /scsi_vhci/ssd@g600000e00d000000000120c500000000
 3. c3t600000E00D000000000120C500010000d0 <FUJITSU-ETERNUS_AHB-0000-2.13TB>
    /scsi_vhci/ssd@g600000e00d000000000120c500010000
 4. c3t600000E00D000000000120C500020000d0 <FUJITSU-ETERNUS_AHB-0000-2.13TB>
    /scsi_vhci/ssd@g600000e00d000000000120c500020000
Specify disk (enter its number): ^C

(Execution example of the luxadm command)

#luxadm probe -p

No Network Array enclosures found in /dev/es

Found Fibre Channel device(s):
Node WWN:500000e0d4583200  Device Type:Disk device
  Logical Path:/dev/rdsk/c0t600000E00D1100000011183200000000d0s2
  Physical Path:
     /devices/scsi_vhci/ssd@g600000e00d1100000011183200000000:c,raw
Node WWN:500000e0d4583200  Device Type:Disk device
  Logical Path:/dev/rdsk/c0t600000E00D1100000011183200010000d0s2
  Physical Path:
     /devices/scsi_vhci/ssd@g600000e00d1100000011183200010000:c,raw
Node WWN:500000e0d4583200  Device Type:Disk device
  Logical Path:/dev/rdsk/c0t600000E00D1100000011183200020000d0s2
  Physical Path:
     /devices/scsi_vhci/ssd@g600000e00d1100000011183200020000:c,raw
Node WWN:500000e0d4583200  Device Type:Disk device
  Logical Path:/dev/rdsk/c0t600000E00D1100000011183200030000d0s2
  Physical Path:
     /devices/scsi_vhci/ssd@g600000e00d1100000011183200030000:c,raw

Occurrence Conditions

A timeout error occurs due to a transmission path failure between the server and the storage systems (*2).

(*2) If a timeout error occurs due to a transmission path failure, the following message appears in /var/adm/messages.

(Message example)
```
WARNING: /scsi_vhci (scsi_vhci0):
    /scsi_vhci/ssd@g6000b5d0006a0000006a0f53000b0000 (ssd0):
        Command Timeout on path fp4/ssd@w2141000b5d6a0f53,2
```
Cause

MPxIO does not switch paths even when a timeout error occurs due to transmission path failures. This is a specification of MPxIO.

Workaround

How to Prevent Problems from Occurring

Install the Multipath Diagnostic Program when configuring a multipath with MPxIO in the ETERNUS AX/AC/HX series or the ETERNUS AB/HB series.

To install the program, the ETERNUS storage system settings must be changed (or a version update of ONTAP or SANtricity OS may be required for some models). For details, refer to Multipath Diagnostic Program User’s Guide.

If the Multipath Diagnostic Program is applied, the failed paths are blocked when a timeout error occurs due to hardware failure on the transmission paths.

Because this result in a path switching, I/O execution does not take time and a system slowdown is prevented.

Note that there are no workarounds to prevent this problem if the MPxIO multipath configuration is used with storage devices other than ETERNUS storage systems. If this problem occurs in these storage devices, consider installing the multipath software recommended by each storage vendor.
Recovery Method After Problems Occur

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SANtricity express configuration manuals ( CA08872-012 )

Learn about Solaris express configuration

Procedure overview

Application of the Multipath Diagnostic Program

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