I agree with Mikhail. That is how I've done it in the past, and it worked
well.
NOTE: Make *sure* the rebalance is *complete* before attempting to remove
the old LUNs! In other words, be sure that V$ASM_OPERATION is empty before
proceeding to remove the old device from the server.
-Mark
On Wed, Sep 8, 2021 at 10:51 AM Mikhail Velikikh <mvelikikh@xxxxxxxxx>
wrote:
Sorry, missed the list in my reply.
Yes, doing it in one command is the best approach. It rebalances the data
only once.
https://docs.oracle.com/en/database/oracle/oracle-database/19/ostmg/alter-diskgroups.html#GUID-6BB31112-8687-4C1E-AF14-D94FFCDA736F
You can add, resize, or drop disks while the database remains online.There will be no rebalance at all if you resize the existing disks (option
Whenever possible, multiple operations in a single ALTER DISKGROUP
statement are recommended. Grouping operations in a single ALTER
DISKGROUP statement can reduce rebalancing operations.
1 in my previous email). It is possible if you use the same storage.
Of course, you have to drop the extra disks that you don't need which
roughly rebalances just a half of data.
On Wed, 8 Sept 2021 at 15:28, Chris Taylor <
christopherdtaylor1994@xxxxxxxxx> wrote:
Ok, so I think I'm following and that makes sense.
In a nutshell it would be add all the new 20T devices *AND* drop the
existing 10T devices in the same command so that the rebalance only
rebalances to the 20T devices?
Is that the theory/idea?
That would definitely prevent the need to use rman to move the datafiles
or anything.
Chris
On Wed, Sep 8, 2021 at 10:09 AM Mikhail Velikikh <mvelikikh@xxxxxxxxx>
wrote:
Hi,
I know ASM devices should be the same size when you rebalance.
If it is an EXTERNAL redundancy disk group, then you can have a disk of
different size there.
12c ASM: Unable To Add New Disks With Dissimilar Size To 12.1.0.2 ASM
Diskgroups (Normal or High Redundancy) Due To ORA-15410 (New 12c ASM
Enhancement Validation/Constraint) (Doc ID 1938950.1)
<https://support.oracle.com/rs?type=doc&id=1938950.1>
Although it is not a best practice, it can be used during such
migrations.
Is that the *only* option here? Anyone have additional
suggestions/thoughts?
1. You can resize the existing disks online, then drop the disks you
don't need.
https://docs.oracle.com/en/database/oracle/oracle-database/19/ostmg/alter-diskgroups.html#GUID-6AEFFA72-7BDC-4AA8-8667-8417AAF3DAC8
It didn't work for me two years ago with AFD. I haven't encountered the
same issue with ASMlib or without any Oracle drivers.
If you don't use AFD, ignore notes below:
Cannot resize ASM Disk using ASM Filter Driver(AFD) online (Doc ID
2099164.1)
ASM not displaying resized disk size in AFD configuration (Doc ID
2263094.1)
Bug 29893839 - ASM CRASHES WHEN RUNNING AFD_REFRESH AFTER THE LUN RESIZE
AT OS LAYER (Doc ID 29893839.8)
2. You can provision new 20TB LUNs and DROP/ADD disk in one ALTER
DISKGROUP command. ASM automatically rebalances data.
https://docs.oracle.com/en/database/oracle/oracle-database/19/ostmg/alter-diskgroups.html#GUID-14E48E96-F5D6-4F41-A8E4-B535CBD3CAE5
Best regards,
Mikhail Velikikh
On Wed, 8 Sept 2021 at 14:46, Chris Taylor <
christopherdtaylor1994@xxxxxxxxx> wrote:
List,
We have a need to restructure our underlying ASM devices to 20T from
10T to reduce the number of luns assigned to a host.
The Total DiskGroup SIze is 163840.00 GB (~ 160 TB) made up of 10TB
devices. (16 Devices)
Our storage admins would like to move these to 20T devices and halve
the number of physical devices presented.
I know ASM devices should be the same size when you rebalance.
I know *one* option is to add the 8 20T devices as candidates and
create a new diskgroup and move the data to the new diskgroup and then drop
the old 10T devices from ASM.
Is that the *only* option here? Anyone have additional
suggestions/thoughts?
Chris
