VTL - Path to backend disk array failed over and was disabled

Asset ID:	1-75-1335432.1
Update Date:	2011-07-07
Keywords:

Solution Type Troubleshooting Sure

Solution 1335432.1 : VTL - Path to backend disk array failed over and was disabled

Applies to:

Sun StorageTek VTL Plus Storage Appliance - Version: 1.0 - Build 1323 to 2.0 - Build 1656 - Release: 1.0 to 2.0
Sun StorageTek VTL Prime System - Version: 1.0 - Build 1813 to 1.1 - Build 2076 [Release: 1.0 to 1.0]
Sun StorageTek VTL Storage Appliance - Version: 4.0 - Build 1221 to 4.0 - Build 1221 [Release: 4.0 to 4.0]
Linux x86
Oracle Solaris on x86 (32-bit)

Purpose

To provide troubleshooting information for a disabled path due to failed over path between VTL and backend disk array.

Last Review Date

July 5, 2011

Instructions for the Reader

A Troubleshooting Guide is provided to assist in debugging a specific issue. When possible, diagnostic tools are included in the document to assist in troubleshooting.

Troubleshooting Details

Most often this is caused by a temporary communication issue between VTL and backend disk array controller. The following steps can be taken to verify:
1. First step is to pull disk array logs and analyze for problems (i.e., possible controller issue or failure). If errors found, correct and reboot VTL.
2. If no problems found on arrays side, check VTL messages file for errors leading up to the path failover. Check for scsi_log_errors and decode sense data (possible causes could be bad FC cables, SFPs or HBAs). If errors found, correct and reboot VTL.
3. If no apparent hardware issues are present, more than likely a temporary issue, bring path back online and monitor for re-occurrence.

NOTE: The only way to bring a disabled path back online is to reboot VTL, so maintenance window will be needed.

Example error messages in VTL server messages file:

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Jun 15 00:52:37 VTL-Node1-net0 genunix: [ID 103500 kern.notice] IOCORE1 [fffffe8000e4ac80] log_scsi_error, acsl 14 0 0 6,
cmd 2A C0 83 45 11 A8 00 02 00 00 00 00 target 00 host 07 driver 00 sense 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
len 262144 ofs 0 type 1 in 0

Jun 15 00:52:37 VTL-Node1-net0 kfsnalias: [ID 188213 kern.notice] IOCORE1 mp_disable_storage_path_by_acsl path(14:0:0:6 is disable)

Jun 15 00:52:37 VTL-Node1-net0 kfsnalias: [ID 188213 kern.notice] IOCORE1 alias_check:pause guid (941e865a-fd4f-4b2c-a563-a0c23dfbebac)

Jun 15 00:52:37 VTL-Node1-net0 kfsnalias: [ID 188213 kern.notice] IOCORE1 failover group ACSL 14 0 0 6 begin

Jun 15 00:52:37 VTL-Node1-net0 kfsnalias: [ID 188213 kern.notice] IOCORE1 resume pdev (941e865a-fd4f-4b2c-a563-a0c23dfbebac), decrease reference number to 0 ,return 0

Jun 15 00:52:37 VTL-Node1-net0 kfsnalias: [ID 188213 kern.notice] IOCORE1 worker_thread: pdev (941e865a-fd4f-4b2c-a563-a0c23dfbebac)
failover group successfully

Jun 15 00:52:39 VTL-Node1-net0 kfsnalias: [ID 188213 kern.notice] IOCORE1 resume_path_to_iocore:prefer group has been resumed

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