Linux VM on ESXi -- RDM Disks - Persistent Naming

[Alzhy]

Bonjour.. Long Time no Post!

We are starting to run "LARGE" Linux Virtual Servers on ESXi 5.0 (why not KVM or RHEV? different story).  And we are using RDM Physical Disks -- so the SAN LUNS are aactually seen as if they are native disks...

scsi_id returns the WWID

SAN Array tools work - i.e. xpinfo (or p900info), evainfo, etc.

Of course multipathing is handled by ESXi -- so for no matter how many paths the SAN LUN has - the Linux Virtual sees just one LUN. And we have a requirement to have persistent naming just like what can be achieved via device-mapper-multipath where in via /etc/multipath.conf - our SAN LUNS can be aliased to have descriptive and persistent names and ownerships even.

I thought of installing device-mapper-multipath as a Quick n' Easy fix, each multipath will of course have only one sub-path and we can still peruse /etc/multipath.conf as if the server is a Physical Linux server. But I think this is really unnecessary as multipathd just adds another layer of complexity, overhead (?)  and possibly even a bit of a drag to the OS' storage stack.

So my question is - is there any way we can do persistent device names to RDM (raw device mapped)  Physical disks in Linux as an ESXi Virtual Server?

As I said earlier, scsi_id works - so we can actually identify the WWIDs of each RDM disk:

]# scsi_id -g -u -s /block/sdd
360060e8004753f000000753f0000292a

I want to have entries for each /dev/sd? in /dev/mapper/SAPDISK00N - just like what we can achieve via device-mapper-multipath. If this means writing UDEV rules -- can soeone point me to resources or an example/quick-through on how this is done?

Graci!

[Alzhy]

Verify the presented is RDM'd correctly bey getting the WWID of the LUN:

/sbin/scsi_id  -g -u -s /block/sdc

If it returns the WWID -- then it means it is properly RDM'd (physical) to the ESXi virtual Linux Server.

In /etc/udev/rules.d: create a rules file named say 99-oracle-asm-disks.rules:

KERNEL=="sd*", SYSFS{vendor}=="HP", PROGRAM=="/sbin/scsi_id -g -u -s /block/%k ", RESULT=="360060e8004753f000000753f0000108b", NAME="mapper/OEMDBDISK01", OWNER="oracle", GROUP="dba", MODE="644", RUN+="/bin/bash -c '/sbin/kpartx -a -p p /dev/mapper/OEMDBDISK01'"

root# udevtest /block/sdc

]# udevtest /block/sdc

main: looking at device '/block/sdc' from subsystem 'block'

run_program: '/lib/udev/usb_id -x'

run_program: '/lib/udev/usb_id' returned with status 1

run_program: '/lib/udev/scsi_id -g -x -s /block/sdc -d /dev/.tmp-8-32'

run_program: '/lib/udev/scsi_id' (stdout) 'ID_VENDOR=HP'

run_program: '/lib/udev/scsi_id' (stdout) 'ID_MODEL=OPEN-V'

run_program: '/lib/udev/scsi_id' (stdout) 'ID_REVISION=5001'

run_program: '/lib/udev/scsi_id' (stdout) 'ID_SERIAL=360060e8004753f000000753f0000108b'

run_program: '/lib/udev/scsi_id' (stdout) 'ID_TYPE=disk'

run_program: '/lib/udev/scsi_id' (stdout) 'ID_BUS=scsi'

run_program: '/lib/udev/scsi_id' returned with status 0

udev_rules_get_name: add symlink 'disk/by-id/scsi-360060e8004753f000000753f0000108b'

run_program: '/lib/udev/path_id /block/sdc'

run_program: '/lib/udev/path_id' (stdout) 'ID_PATH=pci-0000:00:10.0-scsi-0:0:2:0'

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-0:0:2:0'

run_program: '/lib/udev/vol_id --export /dev/.tmp-8-32'

run_program: '/lib/udev/vol_id' returned with status 4

run_program: '/lib/udev/edd_id --export /dev/.tmp-8-32'

run_program: '/lib/udev/edd_id' (stderr) 'no kernel EDD support'

run_program: '/lib/udev/edd_id' returned with status 2

run_program: '/sbin/scsi_id -g -u -s /block/sdc '

run_program: '/sbin/scsi_id' (stdout) '360060e8004753f000000753f0000108b'

run_program: '/sbin/scsi_id' returned with status 0

udev_rules_get_name: rule applied, 'sdc' becomes 'mapper/OEMDBDISK01'

udev_device_event: device '/block/sdc' already in database, validate currently present symlinks

udev_node_add: creating device node '/dev/mapper/OEMDBDISK01', major = '8', minor = '32', mode = '0644', uid = '30181', gid = '200'

udev_node_add: creating symlink '/dev/disk/by-id/scsi-360060e8004753f000000753f0000108b' to '../../mapper/OEMDBDISK01'

udev_node_add: creating symlink '/dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:2:0' to '../../mapper/OEMDBDISK01'

main: run: 'socket:/org/kernel/udev/monitor'

main: run: '/lib/udev/udev_run_devd'

main: run: 'socket:/org/freedesktop/hal/udev_event'

main: run: '/sbin/pam_console_apply /dev/mapper/OEMDBDISK01 /dev/disk/by-id/scsi-360060e8004753f000000753f0000108b /dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:2:0'

main: run: '/bin/bash -c '/sbin/kpartx -a -p p /dev/mapper/OEMDBDISK01''

Enshrine, load and activate the rule:

[root@flpva030 /root]# udevcontrol reload_rules

[root@flpva030 /root]# start_udev

You will NOW have /dev/mapper/ entiries aptly permissioned say for Oracle DB ASM use.