Bug 1325099

Summary: /sys/block/<device_name>/device/rescan: does not exist
Product: Red Hat Enterprise Linux 6 Reporter: Olivier Kaloudoff <olivier.kaloudoff>
Component: doc-DM_MultipathAssignee: Ben Marzinski <bmarzins>
Status: CLOSED NOTABUG QA Contact: ecs-bugs
Severity: medium Docs Contact:
Priority: high    
Version: 6.6CC: adstrong, agk, bmarzins, olivier.kaloudoff, rhel-docs, slevine
Target Milestone: rcKeywords: Documentation
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2016-06-09 20:42:19 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description Olivier Kaloudoff 2016-04-08 08:46:01 UTC
Description of problem:

Hi, 

   in rh-DM_Multipath(EN)-6 (2015-4-13T15:15):

   in the multipath documentation, paragraph 5.2 (Resizing an Online Multipath Device), we see:

Resize your paths. For SCSI devices, writing a 1 to the rescan file for the device causes the SCSI driver to rescan, as in the following command: 
# echo 1 > /sys/block/device_name/device/rescan 


    on the local rhel6.6 system, /sys is mounted correctly, multipath -ll reports our lun and the associated paths, multipath kernel modules are installed correctly .. BUT ...

    there is NO "rescan" file below /sys/block/<device_name>/device/rescan

    there is even NO "/sys/block/<device_name>/device/" 


Version-Release number of selected component (if applicable):

rhel6.6

How reproducible:

log to an rhel6.6 system, setup multipath, connect a san volume, 
perform the command:

find /sys/block -name rescan

NO RESULT IS GIVEN

Steps to Reproduce:
1. setup multipath on rhel6.6
2. setup a lun 
3. perform the command find /sys/block -name rescan 

Actual results:


Expected results:

Command
find /sys/block -name rescan 

Should report at least one result

Additional info:


Document URL: 

Section Number and Name: 

Describe the issue: 

Suggestions for improvement: 

Additional information:

Comment 2 Steven J. Levine 2016-04-11 19:37:49 UTC
Ben:

Could you look at this BZ and let me know if the problem is in the documentation?

Steven

Comment 3 Ben Marzinski 2016-04-12 17:32:47 UTC
No. This is not a documentation problem. This command

# find /sys/block -name rescan

isn't going to show you any "rescan" files.  /sys/block is a directory of symlinks.  For instance (from a rhel-6 system)

# ls -l /sys/block
<snip>
lrwxrwxrwx. 1 root root 0 Feb 25 05:30 sda -> ../devices/pci0000:00/0000:00:01.0/0000:03:0e.0/host2/target2:0:0/2:0:0:0/block/sda
lrwxrwxrwx. 1 root root 0 Feb 25 05:30 sdb -> ../devices/pci0000:00/0000:00:0a.0/0000:06:00.0/host6/rport-6:0-0/target6:0:0/6:0:0:0/block/sdb
lrwxrwxrwx. 1 root root 0 Feb 25 05:30 sdc -> ../devices/pci0000:00/0000:00:0a.0/0000:06:00.0/host6/rport-6:0-0/target6:0:0/6:0:0:1/block/sdc
<snip>

find won't follow symlinks by default.  But RHEL-6 definitely should be storing links to all block devices in /sys/block/<devname>.  By the way, "/sys/block/<devname>/device" is also a symlink, and at least for all scsi devices, it is definitely supposed to be there.

Comment 4 Steven J. Levine 2016-04-14 20:12:27 UTC
Ben: Sorry to put this back in needinfo from you, but I'm not sure what to do here -- do I reassign this bug or close it out as not a bug?

Comment 5 Ben Marzinski 2016-04-18 21:16:35 UTC
Unless some new information appears from the reporter, I'm going to close this as NOTABUG. But, at any rate, there's no documentation work.

Comment 6 Steven J. Levine 2016-06-09 20:42:19 UTC
Closing as per Comment 5.