[SOLVED] Write udev rule to change harddisk timeout
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I want (have to) change the timeout on the harddisks of our VMWare virtual machines in Debian 5. Right now I run a small script to set the timeout manually at boot using rc.local. I would like to have it applied using a udev rule but haven't got a clue where to start. I've been reading and searching but cannot get it to work.
Our vendor provided a script for Suse and RedHat. I've tried changing the RedHat script for Debian but it doesn't work at all.
Here's the udevinfo output of the disk in question.
pay attention to the fact that $devpath is substituted by "/block/sda", so that the path of the timeout file should be "/sys$devpath/device/timeout" (your rule lacks the device directory). As previously suggested you can test the rule with udevtest (when the disk is mounted) and if the rule's action is:
You may also want to refine your rule to match against that particular device, since "KERNEL=="sda", SUBSYSTEM=="block", is a bit too generic. For example you can try to add the "vendor" attribute which identifies a VMware disk and/or the "size" attribute, if fixed.
It's working!!! Thank you so much. The basic stuff is what gets forgotten first I think. I didn't think about to what the devpath variable was pointing, feeling pretty green right now
Anyway, udevtest doesn't work any more since version 0.122 and has been replaced by udevadm test <device>, so
udevadm test /block/sda
srvtest:/etc/udev/rules.d# udevadm test /block/sda
This program is for debugging only, it does not run any program,
specified by a RUN key. It may show incorrect results, because
some values may be different, or not available at a simulation run.
add_matching_files: unable to open '/lib/udev/rules.d': No such file or directory
parse_file: reading '/etc/udev/rules.d/50-udev.rules' as rules file
parse_file: reading '/etc/udev/rules.d/60-persistent-input.rules' as rules file
parse_file: reading '/etc/udev/rules.d/60-persistent-storage-tape.rules' as rules file
parse_file: reading '/etc/udev/rules.d/60-persistent-storage.rules' as rules file
parse_file: reading '/etc/udev/rules.d/60-persistent-v4l.rules' as rules file
parse_file: reading '/dev/.udev/rules.d/61-dev-root-link.rules' as rules file
parse_file: reading '/etc/udev/rules.d/70-persistent-cd.rules' as rules file
parse_file: reading '/etc/udev/rules.d/75-cd-aliases-generator.rules' as rules file
parse_file: reading '/etc/udev/rules.d/75-persistent-net-generator.rules' as rules file
parse_file: reading '/etc/udev/rules.d/80-drivers.rules' as rules file
parse_file: reading '/etc/udev/rules.d/81-vmware-timeout.rules' as rules file
parse_file: reading '/etc/udev/rules.d/91-permissions.rules' as rules file
parse_file: reading '/etc/udev/rules.d/95-late.rules' as rules file
import_uevent_var: import into environment: 'MAJOR=8'
import_uevent_var: import into environment: 'MINOR=0'
import_uevent_var: import into environment: 'DEVTYPE=disk'
import_uevent_var: import into environment: 'PHYSDEVPATH=/devices/pci0000:00/0000:00:10.0/host0/target0:0:0/0:0:0:0'
import_uevent_var: import into environment: 'PHYSDEVBUS=scsi'
import_uevent_var: import into environment: 'PHYSDEVDRIVER=sd'
udevtest: looking at device '/block/sda' from subsystem 'block'
udev_rules_get_name: add symlink 'block/8:0'
match_rule: '/sys/block/sda/whole_disk' does not exist
udev_node_mknod: mknod(/dev/.tmp-8-0, 060600, (8,0))
udev_node_mknod: chmod(/dev/.tmp-8-0, 060600)
udev_node_mknod: chown(/dev/.tmp-8-0, 0, 0)
run_program: 'scsi_id --export --whitelisted --device=/dev/.tmp-8-0'
run_program: '/lib/udev/scsi_id' returned with status 1
run_program: 'edd_id --export /dev/.tmp-8-0'
run_program: '/lib/udev/edd_id' (stderr) 'no kernel EDD support'
run_program: '/lib/udev/edd_id' returned with status 2
run_program: 'path_id /block/sda'
run_program: '/lib/udev/path_id' (stdout) 'ID_PATH=pci-0000:00:10.0-scsi-0:0:0:0'
run_program: '/lib/udev/path_id' returned with status 0
udev_rules_get_name: add symlink 'disk/by-path/pci-0000:00:10.0-scsi-0:0:0:0'
run_program: 'vol_id --export /dev/.tmp-8-0'
run_program: '/lib/udev/vol_id' (stderr) '/dev/.tmp-8-0: unknown volume type'
run_program: '/lib/udev/vol_id' returned with status 4
udev_rules_get_name: no node name set, will use kernel name 'sda'
udev_device_event: device '/block/sda' already in database, cleanup
udev_node_add: creating device node '/dev/sda', major=8, minor=0, mode=0660, uid=0, gid=6
udev_node_update_symlinks: update symlink 'block/8:0' of '/block/sda'
udev_db_get_devices_by_name: found index directory '/dev/.udev/names/block\x2f8:0'
update_link: found 1 devices with name 'block/8:0'
update_link: found '/block/sda' for 'block/8:0'
update_link: compare (our own) priority of '/block/sda' 0 >= 0
update_link: 'block/8:0' with target 'sda' has the highest priority 0, create it
udev_node_update_symlinks: update symlink 'disk/by-path/pci-0000:00:10.0-scsi-0:0:0:0' of '/block/sda'
udev_db_get_devices_by_name: found index directory '/dev/.udev/names/disk\x2fby-path\x2fpci-0000:00:10.0-scsi-0:0:0:0'
update_link: found 1 devices with name 'disk/by-path/pci-0000:00:10.0-scsi-0:0:0:0'
update_link: found '/block/sda' for 'disk/by-path/pci-0000:00:10.0-scsi-0:0:0:0'
update_link: compare (our own) priority of '/block/sda' 0 >= 0
update_link: 'disk/by-path/pci-0000:00:10.0-scsi-0:0:0:0' with target 'sda' has the highest priority 0, create it
udevtest: run: '/bin/sh -c 'echo 180 > /sys/block/sda/device/timeout''
udevtest: run: 'socket:@/org/kernel/udev/monitor'
which looked pretty perfect! After a reboot of my testserver the correct value was presented. Thanks again for your help. Moltes graciès!