Skip to Main Content
Forums

Database Software

Announcement

For appeals, questions and feedback about Oracle Forums, please email oracle-forums-moderators_us@oracle.com. Technical questions should be asked in the appropriate category. Thank you!

Interested in getting your voice heard by members of the Developer Marketing team at Oracle? Check out this post for AppDev or this post for AI focus group information.

Cannot open 2 Virtual Machines at the same time to access the same Database

user8860348Jan 24 2012 — edited Jan 25 2012
Folks,

Hello.
I am installing Oracle Database 11gR2 RAC system using 2 Virtual Machines (rac1 and rac2) on the top of VMPlayer 3.

The VM rac1 and rac2 run correctly when one of them is shutdown.
Their locations are F:\VM_RAC\rac1 and F:\VM_RAC\rac2.


While rac2 is running, I open rac1. But this error message comes up:

Error: "Cannot open the disk F:\VM_RAC\sharerac\asm1.vmdk or one of snapshot disks it depends on. Reason: failed to lock the file."


While rac1 is running, I open rac2. But this error message comes up:

Error: "Cannot open the disk F:\VM_RAC\sharerac\asm1.vmdk or one of snapshot disks it depends on. Reason: failed to lock the file."


The 2 error messages are the same. This means I cannot open 2 VMs rac1 and rac2 at the same time. When we run RAC system, we have to open 2 machines or more than 2 machines at the same time so that all machines can access the same Database Server.

My question is:

Can any folk tell me how to have rac1 and rac2 run at the same time ?

Thanks.
This post has been answered by BryanWood on Jan 25 2012
Jump to Answer

Comments

BryanWood
You need to disable disk locking, which ordinarily is performed by the first VM to prevent any other VMs from corrupting your vmdk files via uncoordinated writes. You will have to shutdown both of your VMs and edit the *.vmx flat file for each, adding lines like the following (settings taken from workstation 6, but should be nearly identical settings for VM Player 3.x):

http://crosbysite.blogspot.com/2007/10/clustering-in-vmware-workstation-6.html

scsi1.sharedbus = "Virtual"
disk.locking = "false"
diskLib.dataCacheMaxSize = "0"
diskLib.dataCacheMaxReadAheadSize = "0"
diskLib.dataCacheMinReadAheadSize = "0"
diskLib.dataCachePageSize = "4096"
diskLib.maxUnsyncedWrites = "0"

A few comments:

- your shared disks (scsi1) must be on a separate virtual scsi bus than the boot disk (scsi0), to allow setting the sharedbus flag as seen above.
- you must also ensure the cache parameters and unsynced writes settings are set to guarantee that all IO is immediately flushed to the vmdk file so the other VM can immediately access the latest version of data.
1 person found this helpful
user8860348
Folks,

Hello. Thanks a lot for replying.

Because 2 Virtual Machines rac1 and rac2 share the same disk F:\VM_RAC\sharerac\asm1.vmdk and cause the problem, can we have rac1 and rac2 use different disks ?

For example,
Let rac1 uses disk F:\VM_RAC\sharerac\asm1.vmdk
Let rac2 uses disk F:\VM_RAC\sharerac\asm2.vmdk

If yes, how to have rac1 use asm1.vmdk and rac2 uses asm2.vmdk ?
BryanWood
Answer
Unfortunately no, Oracle RAC requires all nodes have access the same set of shared disks. If your database resides within ASM, each ASM instance (one per node) must also see the same set of disks to mount the ASM diskgroup containing the database's datafiles.

Best Regards,
Bryan Wood
Marked as Answer by user8860348 · Sep 27 2020
user8860348
Folks,

Hello. thanks a lot for replying.
I have edited the VMX files for rac1 and rac2. Both VMs can open at the same time now. Thanks again.
1 - 4
Locked Post
New comments cannot be posted to this locked post.

Post Details

Locked on Feb 22 2012
Added on Jan 24 2012
#cluster, #performance-availability, #rac-asm-clusterware-installation
4 comments
2,311 views