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Device Name Change Occurs in Red Hat 6.2 to Which S5500T LUNs Are Mapped

Publication Date:  2018-10-16 Views:  312 Downloads:  0

Issue Description

A Huawei S5600T storage system is directly connected to two Inspur servers through Fibre Channel links. The two servers run Red Hat 6.2 and form a two-node Oracle 10g cluster. It is confirmed that multipathing software is correctly installed on the two servers, but one of the servers has the device name change problem.

Handling Process

The customer confirmed that a USB flash drive was inserted during a system startup. After removing the USB flash drive and restarting the system, the problem is solved.

Root Cause

An analysis of operating system logs indicates that a USB device obtains the device name. See the following log information:
Feb 26 08:06:18 ycweb1 kernel: scsi 4:0:0:0: Direct-Access     SEAGATE  ST3300657SS      0008 PQ: 0 ANSI: 5
Feb 26 08:06:18 ycweb1 kernel: scsi 4:0:1:0: Direct-Access     SEAGATE  ST3300657SS      0008 PQ: 0 ANSI: 5
Feb 26 08:06:18 ycweb1 kernel: scsi 4:0:2:0: Direct-Access     SEAGATE  ST3300657SS      0008 PQ: 0 ANSI: 5
Feb 26 08:06:18 ycweb1 kernel: scsi 4:0:3:0: Direct-Access     SEAGATE  ST3300657SS      0008 PQ: 0 ANSI: 5
Feb 26 08:06:18 ycweb1 kernel: scsi 4:2:0:0: Direct-Access     LSI      MR9240-8i        2.12 PQ: 0 ANSI: 5
Feb 26 08:06:18 ycweb1 kernel: scsi 4:2:1:0: Direct-Access     LSI      MR9240-8i        2.12 PQ: 0 ANSI: 5
Feb 26 08:06:18 ycweb1 kernel: sd 4:2:0:0: [sda] 584843264 512-byte logical blocks: (299 GB/278 GiB)
Feb 26 08:06:18 ycweb1 kernel: sd 4:2:1:0: [sdb] 584843264 512-byte logical blocks: (299 GB/278 GiB)
Feb 26 08:06:18 ycweb1 kernel: [0x0000534200010090][INFO][UP][mppLnx_sd_probe, 2218][4294683911] UP_Event:H7T0L0 is virtual LUN, added by UltraPath.
Feb 26 08:06:18 ycweb1 kernel: sd 7:0:0:0: [sdc] 2097152 512-byte logical blocks: (1.07 GB/1.00 GiB) //Storage disks start from sdc.

Feb 26 17:19:09 ycweb1 kernel: [0x000053420001025a][ERR][UP][mpp_BuildRdacinfo, 9005][4294681449] The Vendor PNY     USB 2.0 FD      8192
is Invalid ! //USB device
Feb 26 17:19:09 ycweb1 kernel: [0x0000534200010092][WARN][UP][mppLnx_sd_probe, 2247][4294681449] Exit mppLnx_sd_probe,H7T0L0 can't be managed by UltraPath.
Feb 26 17:19:09 ycweb1 kernel: sd 7:0:0:0: [sdc] 31703040 512-byte logical blocks: (16.2 GB/15.1 GiB) //sdc is obtained by a USB device.
Feb 26 17:19:09 ycweb1 kernel: [0x0000534200010090][INFO][UP][mppLnx_sd_probe, 2218][4294683931] UP_Event:H8T0L0 is virtual LUN, added by UltraPath.
Feb 26 17:19:09 ycweb1 kernel: sd 8:0:0:0: [sdd] Attached SCSI disk   //Storage disks start from sdd. By comparison, it can be inferred that the device name change is caused by a USB device that obtains device name sdc. The USB device sometimes can be identified by the system but sometimes cannot. Check the USB port on the host.

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