|Summary:||udev vol_id probe of passive/unreadable devices causes slow bootup|
|Product:||Red Hat Enterprise Linux 5||Reporter:||John Ruemker <jruemker>|
|Component:||udev||Assignee:||Harald Hoyer <harald>|
|Status:||CLOSED ERRATA||QA Contact:||qe-baseos-daemons|
|Version:||5.2||CC:||azelinka, greg.marsden, john.sobecki, jwest, kvolny, pknirsch, sdodson, tao|
|Fixed In Version:||udev-095-14.23.el5||Doc Type:||Bug Fix|
Previously, the udev helper application 'vol_id' ran several times if a device was unreadable. This caused a massive delay for the bootup process on some machines. With this update, 'vol_id' checks whether a device is readable only once and no longer causes a delay.
|Last Closed:||2011-01-13 22:59:25 UTC||Type:||---|
|oVirt Team:||---||RHEL 7.3 requirements from Atomic Host:|
|Cloudforms Team:||---||Target Upstream Version:|
Description John Ruemker 2008-07-23 18:24:04 UTC
Description of problem: udev takes a very long time (~20 minutes) to start on systems connected to an active/passive SAN with many LUNs. It appears to be taking a long time on running vol_id on the passive paths. Running this command on one LUN takes between 2-3 minutes [root@prod-xen2 ~]# time /lib/udev/vol_id --export /dev/sdc real 1m58.681s user 0m0.000s sys 0m0.003s There is an upstream patch designed to correct this: http://git.kernel.org/?p=linux/hotplug/udev.git;a=commitdiff;h=73ff769c90307e9ef2947c7ba013626fb65c1478 Version-Release number of selected component (if applicable): Looking at the logs you can see it try over and over Jul 23 12:11:31 prod-xen2 kernel: end_request: I/O error, dev sdc, sector 0 Jul 23 12:11:31 prod-xen2 kernel: Buffer I/O error on device sdc, logical block 0 Jul 23 12:11:34 prod-xen2 kernel: end_request: I/O error, dev sdc, sector 0 Jul 23 12:11:37 prod-xen2 kernel: end_request: I/O error, dev sdc, sector 0 Jul 23 12:11:37 prod-xen2 kernel: printk: 1 messages suppressed. Jul 23 12:11:37 prod-xen2 kernel: Buffer I/O error on device sdc, logical block 0 Backporting the above patch to current udev-095-14.16 and running vol_id is much better: [root@prod-xen2 ~]# time ./vol_id --export /dev/sdc real 0m3.138s user 0m0.000s sys 0m0.001s and only probes the device once: Jul 23 14:20:31 prod-xen2 kernel: end_request: I/O error, dev sdc, sector 0 Jul 23 14:20:31 prod-xen2 kernel: Buffer I/O error on device sdc, logical block 0
Comment 1 John Ruemker 2008-07-23 18:25:47 UTC
Created attachment 312503 [details] vol_id patch for udev-095-14.16
Comment 4 RHEL Product and Program Management 2009-11-06 19:24:10 UTC
This request was evaluated by Red Hat Product Management for inclusion, but this component is not scheduled to be updated in the current Red Hat Enterprise Linux release. If you would like this request to be reviewed for the next minor release, ask your support representative to set the next rhel-x.y flag to "?".
Comment 5 John Sobecki 2009-12-11 20:23:52 UTC
Apple computer requested this patch for Oracle Enterprise Linux as they are seeing these delays with Sun storage using rdac multipathing.
Comment 8 Karel Volný 2010-11-25 13:31:16 UTC
please, what hardware can be used to test with?
Comment 9 Harald Hoyer 2010-11-25 13:38:58 UTC
hmm, you might try with a blank cd-rw in a cdrom
Comment 11 Martin Prpič 2010-12-06 14:13:19 UTC
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: Previously, the udev helper application 'vol_id' ran several times if a device was unreadable. This caused a massive delay for the bootup process on some machines. With this update, 'vol_id' checks whether a device is readable only once and no longer causes a delay.
Comment 13 errata-xmlrpc 2011-01-13 22:59:25 UTC
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2011-0073.html