Oracle RAC ASM setup on a shared Netapp SAN partition in RHES
Posted on 2008-06-16
We have 3 RHES servers (V4.6) - the DBA would like Oracle RAC ASM on all 3 servers
access a common NetApp SAN raw disk partition.
We found that /dev/mapper/mpath1 on server 1 is /dev/mapper/mpath0 on server 2
& yet a different device name on the 3rd server. Good thing is /dev/mapper/mpathx
stays permanently linked to the same disk partition each time the RHES servers are
rebooted. If we use /dev/mpath/pathx, it changes each time servers are rebooted,
ie on server 1, after a reboot, the value in /dev/mpath/pathx will need to be changed
so as to access back the same disk partition but if we used /dev/mapper/pathx, it's
stays the same after reboots.
The DBA has set up Oracle RAC clustering (using sort of ASM tool - I'm not sure as
I'm no DBA but Unix Admin). She's sure that on all the servers, she has used the
same SAN disk partition & is able to create the database successfully. So on all
the servers, ORACLE_SID=+ASM2 & when she went into each of the servers to
do a "select" to retrieve data, only on server1 it returns data while on the other
servers, nothing was returned.
I'm not sure how the DBA ensure she's accessing the same partition - is there anyway
I can verify this other than
" formatting (using fdisk) on each of the server the disk partition
to a character device, mount the formatted character device to a mount point on each
server, create a dummy file, say test.txt & go into the other 2 servers to check if test.txt
is there " - to do this, she'll lose her work done so far.
Also, if RAC clustering is used, is Linux clustering still needed or RAC clustering can
coordinate the IO between the servers? If Linux clustering is needed, kindly let me
know the Linux command to start up the clustering service
We have another set of older Linux servers which the outsourced DBA told us
they used /dev/raw... device files which also connects to Netapp SAN disk partitions
& no Linux clustering is running but this set of servers is owned by the outsourced
DBAs/ vendors & I have yet o verify what she said is true.
Lastly, we're contemplating if we should use character device instead of raw device.
Can Oracle ASM be used on a non-raw (character) device Unix file system?
I'm completely newbie to Oracle/RAC/ASM & NetApp SAN, so bear with me.