I have 2 identical Dell R720 servers running identical Oracle Enterprise Linux(RHEL)6.4.
Both servers (supposedly) configured in exactly the same way. However, one of the servers is behaving differently.
Every other reboot its local HDD name(and related partitions) flip from /dev/sda to /dev/sdj.
This is problematic because this server is configured with multipathd, and if this flip happens this config does not match other server and Oracle DB(or its clusterware) complains that nodes are not configured identically.
Why does one server has a consistent device names while the other server keeps flipping back and forth?
How can I make local hdd to consistently be /dev/sda?
edit:
I created a rules file in /etc/udev/rules.d with the following rule, but it doesn't seem to be working
KERNEL=="sd*" , PROGRAM="scsi_id --page=0x83 -–whitelisted --device=/dev/%k",RESULT=="36b8ca3a0e58a3f00195c25c8117a6822", NAME="sda"
Better than fighting with
udevto force a device name for a given device, a permanent solution is to use UUIDs. This is valid for any device known to the device-mapper.This way, you don't have to worry if you add extra disks to your host. The UUID identifier guaranties that the right device will be used.
Use aliases, or user_friedly_names or do it with udev. All of these are documented in RHEL Storage Administration Guide:
Maybe you could use /dev/disk/* tree instead of mapped /dev/sd*
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/persistent_naming.html
http://www.centos.org/docs/5/html/5.2/Virtualization/sect-Virtualization-Virtualized_block_devices-Configuring_persistent_storage_in_a_Red_Hat_Enterprise_Linux_5_environment.html
if you're using multipathd, then you should not have to care weather the disks name is
/dev/sdaor/dev/sdj. Use the device name created withmultipathdshown withmultipath -ll. That name is persistent. The/dev/sd*names only refer to a single path...Never use raw disk partitioning. Use LVM. You will end up with the very same configuration on both hosts, regardless of the UUID/WWID disk naming schema.