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Oracle Linux 5.8 and UDEV issues…

I just did an update from Oracle Linux 5.7 to 5.8 on one of my VirtualBox RAC installations and things are not looking to clever at the moment. After a reboot, the ASM instances and therefore the database instances wouldn’t restart. A quick look showed the ASM disks were not visible. On this installation I was using UDEV, rather than ASMLib. In checking the UDEV rules I noticed the scsi_id command on OL5.8 doesn’t report an ID for partitions on disks, only the disks themselves. For example, on OL5.7 I get this,

# /sbin/scsi_id -g -u -s /block/sdb/sdb1
SATA_VBOX_HARDDISK_VBd306dbe0-df3367e3_
#

On OL5.8 I get this,

# /sbin/scsi_id -g -u -s /block/sdb/sdb1
#

If I run it against the disk, rather than the partition it works fine.

This has literally just happened, so I’ve done no further investigation, but I thought it was worth putting out there in case anyone was about to start an OS update on something they cared about. :)

At this point I’m not discounting that I’ve screwed up somewhere. My next plan is to install three clean VMs (OL 5.6, 5.7 and 5.8) and check the output of scsi_id on each of them. If that turns out OK, then I’ve screwed something else and you can probably ignore this post. I might not get to try it out until tomorrow. Either way, I’ll update this post with the results of that test.

Cheers

Tim…

Update 1: It’s definitely changed. See the following.

# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.6 (Tikanga)
# /sbin/scsi_id -g -u -s /block/sda/sda1
SATA_VBOX_HARDDISK_VB54dff07f-931ce4d7_
#

# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.7 (Tikanga)
# /sbin/scsi_id -g -u -s /block/sda/sda1
SATA_VBOX_HARDDISK_VBx180d717-f896e661_
#

# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.8 (Tikanga)
# /sbin/scsi_id -g -u -s /block/sda/sda1
#

Update 2: As John Sobecki correctly pointed out in the comments, the title of the post is misleading. UDEV is not at fault here. The problem is the “/sbin/scsi_id” command is behaving differently, which is making my rules useless. The UDEV issue is the symptom, not the cause. The post is clearly focusing on the scsi_id issue, but I’ve picked a pretty bad title to go with it. :)

Update 3: John Sobecki pointed me at “[block] fail SCSI passthrough ioctls on partition devices CVE-2011-4127″, a mainline kernel security fix that seems to be the cause of this. It affects all new kernels which include this change (RHEL5/6, UEK etc). Oracle are testing the impact of this. Initially ASMLib and OCFS seem unaffected.

Update 4: MOS Note 1438604.1 (currently in review) contains more information about this issue. ASMLib and OCFS are unaffected by CVE-2011-4127, so ASMLib should probably be used in preference to UDEV with newer kernels.