UDEV Rules to enable device name persistence

Hi All,

This is neto from Brazil

How are you?

Linux doesn't guarantee a persistence device name for SCSI devices. This can cause all kinds of fun with your LUNS because the device name associated with LUNS presented from the NetApp can get shuffled around.

A solution is: Setup UDEV Rules to enable device name persistence.

Note: NOT Needed for Data Disks when ASMLib is used. In this case only setup device persistence for the OCR and VOTE disks.

1. White List the NetApp LUNS (devices)

• add a line to /etc/scsi_id.config

vendor="NETAPP", model=LUN, options=-g

- This allows UDEV to obtain the UUID from LUNS

- Without this entry the "-g" option will always be needed on the scsi_id command to get any results

- The Vendor and Model information can be obtained by this:

scsi_id -gxs /block/sdg
 ID_VENDOR=NETAPP <--Here
 ID_MODEL=LUN   <--And Here
 ID_REVISION=0.2
 ID_SERIAL=360a980004334616e52344746596b2d67
 ID_TYPE=disk
 ID_BUS=scsi

Obtain list of LUNS from the NetApp Controllers

• sanlun lun show all

sanlun lun show all
 filer:    lun-pathname   device filename adapter protocol     lun size     lun state
   tng1: /vol/css1/ocr1     /dev/sdg     host9  iSCSI    280m (293601280)   GOOD
   tng2: /vol/css2/ocr2     /dev/sdb     host8  iSCSI    280m (293601280)   GOOD
   tng1: /vol/css1/vote1    /dev/sdh     host9  iSCSI    280m (293601280)   GOOD
   tng2: /vol/css2/vote2    /dev/sdc     host8  iSCSI    280m (293601280)   GOOD
   tng1: /vol/css1/vote3    /dev/sdi     host9  iSCSI    280m (293601280)   GOOD
   .
   .
   .

3. Get the Serial number for each SCSI Device (LUN)

• scsi_id -p 0x83 -s /block/sdg
• scsi_id -p 0x83 -s /block/sdb
• scsi_id -p 0x83 -s /block/sdh
• scsi_id -p 0x83 -s /block/sdc
• scsi_id -p 0x83 -s /block/sdi

Sample Output:

scsi_id -s /block/sdi
360a9800043346161613447454776694c

4. Create a New UDEV rules file to statically name the SCSI Devices

• cd /etc/udev/rules.d
• vi 99-static-scsi-names.rules

NOTE: This example includes setting ownership and permissions for Oracle RAC Clusterware Disks

#----------------------------
#BEGIN: OCR DISKS
#----------------------------
#css1/ocr
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="360a98000433461616134474541327154", NAME="sdOCR1%n", OWNER="root", GROUP="oinstall", MODE="0640"
#css2/ocr
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="360a980004334616e5234474541572f32", NAME="sdOCR2%n", OWNER="root", GROUP="oinstall", MODE="0640"
#----------------------------
#BEGIN: VOTE DISKS
#----------------------------
#css1/vote
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="360a980004334616161344745416b6542", NAME="sdVOTE1%n", OWNER="oracle", GROUP="oinstall", MODE="0640"
#css2/vote
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="360a980004334616e52344745416e4332", NAME="sdVOTE2%n", OWNER="oracle", GROUP="oinstall", MODE="0640"
#fra1/vote
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="360a9800043346161613447454776694c", NAME="sdVOTE3%n", OWNER="oracle", GROUP="oinstall", MODE="0640"

5. Execute the new rules file

• udevcontrol reload_rules
• start_udev

OR

• reboot

Thank you very much my friend Allan Wilson and Lou Lydiksen.

All the best

neto
NetApp - My reason to live!