关于rescan-scsi-bus.sh脚本的来历和使用注意事项

关于rescan-scsi-bus.sh脚本的来历和使用注意事项


1.rescan-scsi-bus.sh在sg3_utils-1.28-8.el6.x86_64中,如下试验:


安装sg3_utils-1.28-8.el6.x86_64 包.

[root@localhost repodata]# yum install sg3_utils*
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Setting up Install Process
rhel-source                                                                                                                                                             | 4.1 kB     00:00 ... 
Package sg3_utils-libs-1.28-8.el6.x86_64 already installed and latest version
Resolving Dependencies
--> Running transaction check
---> Package sg3_utils.x86_64 0:1.28-8.el6 will be installed
--> Finished Dependency Resolution


Dependencies Resolved


===============================================================================================================================================================================================
 Package                                       Arch                                       Version                                        Repository                                       Size
===============================================================================================================================================================================================
Installing:
 sg3_utils                                     x86_64                                     1.28-8.el6                                     rhel-source                                     500 k


Transaction Summary
===============================================================================================================================================================================================
Install       1 Package(s)


Total download size: 500 k
Installed size: 1.3 M
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : sg3_utils-1.28-8.el6.x86_64                                                                                                                                                 1/1 
  Verifying  : sg3_utils-1.28-8.el6.x86_64                                                                                                                                                 1/1 


Installed:
  sg3_utils.x86_64 0:1.28-8.el6                                                                                                                                                                


Complete!
[root@localhost repodata]# 

[root@localhost repodata]# yum provides /usr/bin/rescan-scsi-bus.sh
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
sg3_utils-1.28-8.el6.x86_64 : Utilities for devices that use SCSI command sets--->>>>在sg3_utils-1.28-8.el6.x86_64中.
Repo        : rhel-source
Matched from:
Filename    : /usr/bin/rescan-scsi-bus.sh


sg3_utils-1.28-8.el6.x86_64 : Utilities for devices that use SCSI command sets
Repo        : installed
Matched from:
Other       : Provides-match: /usr/bin/rescan-scsi-bus.sh


[root@localhost repodata]# 

2.对有数据库在运行的操作系统,禁止使用rescan-scsi-bus.sh 的-i选项来运行rescan-scsi-bus.sh,原因见:

	Executing rescan-scsi-bus.sh -i ( LIP flag ) caused RAC Node to Hang (Doc ID 1645143.1)

What is LIP ( Loop Initialization Protocol ) ?
LIP scans the interconnect and causes the SCSI layer to be updated to reflect the devices currently on the bus.
A LIP is, essentially, a bus reset, and will cause device addition and removal. 
This procedure is necessary to configure  a new SCSI target on a Fibre Channel interconnect. 
Bear in mind that issue_lip is an asynchronous operation. The command may complete before the entire scan has completed.

What LIP Reset may cause?

Loop Initialization Protocol method to scan the HBA’s can cause delay 
and I/O timeouts if the HBA/Device is in use and can also remove devices unexpectedly. 
Hence performing the scan using this method is not recommended on any production server where the SAN Devices are already configured in use. 
This type of scan is recommended on a newly built server to scan all the LUNS/Devices.
LIP is normally executed when Server boot.

3.Running "rescan-scsi-bus.sh -r" Can Remove Online Devices (Doc ID 2131357.1)