Oracle ASM
Introduction:
Oracle introduced ASM (Automatic storage management) with 10 g version ,ASM is a logical volume Manager owned by oracle and it helps to create logical volumes on physical disks to store the database and its components and it widely used in Real Application Cluster,ASM is built on OMF,ASM acts as a buit in oracle volume manager by handling striping and mirroring functions ,previously managed by third party tools,is a Poratable volume manager to manage pool of shared disks,ASM is an instance not a database will have separate SGA and set of bg process.
Raw Devices
OCFS2 ----->Orcale clusterd File system
ASM------->Automatic Storage Management
is a part grid of infrastructure software in 10g ,we have separate home for ASM installed from 11g, one single home for clusterware and ASM with grid infra home
eg : /u01/app/11.2.0/grid
/u01/app/12.2.0/grid
Manages oracle data files (eg:DATA) spreads data across disks for faster performance and work load balance
Note: Oracle recommends to manage with minimum 4 disks for each disk group,supports online disks reconfiguration and rebalancing provides adjustable rebalncing speed,for every node,we have ASM instance default installed while grid software
rac1 --->+ASM1
rac2---->+ASM2
ps -ef |grep pmon
To view the information in grid will usse performance views with gv$
gv$session
gv$process
gv$instance
gv$database
for finding information on every instance using global/grid views
number of nodes -4
node-1
node-2
node-3
node-4
Number of ASM Instances :4(eg: +ASM1,+ASM2,+ASM3,+ASM4)
Number of ASM Instance on each node :1(eg: on rac1,+ASM1)
Number of RDBMS Instances :3 prod,dev.test
Number of RDBMS Instances on each node :3(prod1,dev1,test1)
Each database number of instance on 4 node? 4
eg:2dbs,each db has 4 instances if 4 nodes
prod(DB)-->prod1,prod2,prod3,prod4(Instances)
Test(DB)--->test1,test2,test3,test4
eg:
3 databases in a cluster
rac1----> +ASM1,prod1,dev1,test1
rac2---->+ASM2,prod2,dev2,test2
sql>select inst_id,instance_number,host_name,status from gv$instance;
grid infrastructure
clusterware|ASM
cluster--clusterware
storage--ASM--automatic storage management
Linux/oradata-->dbfiles--->managed linux os--->notshared--->single instance accessed
rac1
rac2
rac3
rac4
access-->shared storage across multiple nodes/server with in a cluster
asmdisk1,asmdisk2 -disk1,disk2--drivers--asmdrivers--boot/list
p1
p2
p3
p4
p5
one more cluster -it own his shared storage ASM is a volume manager to manage pool of disks
using logical storage unit as disk group associated with one or more physical disks
two disk groups
DATA--->dbfiles,redo,controfile,spfile,ocr,vote
FRA---->archives,backupsets
min 4 disks avail for each disk group
DATA---->asmdisk1,asmdisk2,asmdisk3(3 dsiks)can add more
FRA ----->asmdisk4,asmdisk5(2 disks)
online---->add disk without downtime spreads data across disks forfatsre performance can be rebalanced by adding disks/removing disks
ASM is an instance,not a database on everynode,default one ASM instance runs/starts on a clusterware startup
connect and verify the instances status of every node with in a cluster from any one single instance using gv$instance
select inst_id,instance_name,instance_number,status from gv$instance;
number of rdbms instances on 4 nodes
rac1-->prod1,dev1,test1
rac2--->prod2,dev2,test2
rac3--->prod3,dev3,test3
rac4--->prod4,dev4,test4
including ASM -->overall on a 4 node cluster with 3 database 3 rdbms*4 nodes=12 inst+4 ASM=16 instances
Log in to asm
Tools
asmca - configuration assistant
ascmd - command line
$asmcmd
mkdir
cp
ls
mv
du
xhost +
su - oracle
.grid_env
$asmca
create diskgroups/add disks/drop disks
mount diskgroups/Dismount diskgroup/local
Oracle recommends to manage with min three diskgroups
DATA - datafiles,redo,control,ocr,voting disk
FRA - fast recovery area - rman,archives,flashback logs,redo
,control files
Each diskgroup may have one or more disks
Brief few views in ASM
v$asm_file
v$asm_diskgroups
V$asm_disks
v$asm_operation
v$asm_disk_stat
v$asm_client
sql>select hot_used_mb,cold_used_mb,free_mb,total_mb,name,label,path from v$asm_disk;
sqlplus '/as sysasm'
SQL> SELECT name, free_mb, total_mb, free_mb/total_mb*100 as percentage FROM v$asm_diskgroup;
How to configure ASM diskstring to discover the disks while boot?
sql>alter system set asm_diskstring='/dev/oracleasm/disks/*' sid='*' scope=spfile;
Note: sid='*' to apply in every instance with in a cluster.
SQL> alter system set asm_diskgroups=DATA sid='*';
Mounting diskgroups in ASM
sql>alter diskgroup all mount;
ASM - DiskGroups
set wrap off
set lines 155 pages 9999
col "Group Name" for a6 Head "Group|Name"
col "Disk Name" for a10
col "State" for a10
col "Type" for a10 Head "Diskgroup|Redundancy"
col "Total GB" for 9,990 Head "Total|GB"
col "Free GB" for 9,990 Head "Free|GB"
col "Imbalance" for 99.9 Head "Percent|Imbalance"
col "Variance" for 99.9 Head "Percent|Disk Size|Variance"
col "MinFree" for 99.9 Head "Minimum|Percent|Free"
col "MaxFree" for 99.9 Head "Maximum|Percent|Free"
col "DiskCnt" for 9999 Head "Disk|Count"
prompt
prompt ASM Disk Groups
prompt ===============
SELECT g.group_number "Group"
, g.name "Group Name"
, g.state "State"
, g.type "Type"
, g.total_mb/1024 "Total GB"
, g.free_mb/1024 "Free GB"
, 100*(max((d.total_mb-d.free_mb)/d.total_mb)-min((d.total_mb-d.free_mb)/d.total_mb))/max((d.total_mb-d.free_mb)/d.total_mb) "Imbalance"
, 100*(max(d.total_mb)-min(d.total_mb))/max(d.total_mb) "Variance"
, 100*(min(d.free_mb/d.total_mb)) "MinFree"
, 100*(max(d.free_mb/d.total_mb)) "MaxFree"
, count(*) "DiskCnt"
FROM v$asm_disk d, v$asm_diskgroup g
WHERE d.group_number = g.group_number and
d.group_number <> 0 and
d.state = 'NORMAL' and
d.mount_status = 'CACHED'
GROUP BY g.group_number, g.name, g.state, g.type, g.total_mb, g.free_mb
ORDER BY 1
/
------------------------------------------------------
ASM - Disk in Use
-----------------------------------------------
prompt ASM Disks In Use
prompt ================
col "Group" for 999
col "Disk" for 999
col "Header" for a9
col "Mode" for a8
col "State" for a8
col "Created" for a10 Head "Added To|Diskgroup"
--col "Redundancy" for a10
--col "Failure Group" for a10 Head "Failure|Group"
col "Path" for a19
--col "ReadTime" for 999999990 Head "Read Time|seconds"
--col "WriteTime" for 999999990 Head "Write Time|seconds"
--col "BytesRead" for 999990.00 Head "GigaBytes|Read"
--col "BytesWrite" for 999990.00 Head "GigaBytes|Written"
col "SecsPerRead" for 9.000 Head "Seconds|PerRead"
col "SecsPerWrite" for 9.000 Head "Seconds|PerWrite"
select group_number "Group"
, disk_number "Disk"
, header_status "Header"
, mode_status "Mode"
, state "State"
, create_date "Created"
--, redundancy "Redundancy"
, total_mb/1024 "Total GB"
, free_mb/1024 "Free GB"
, name "Disk Name"
--, failgroup "Failure Group"
, path "Path"
--, read_time "ReadTime"
--, write_time "WriteTime"
--, bytes_read/1073741824 "BytesRead"
--, bytes_written/1073741824 "BytesWrite"
, read_time/reads "SecsPerRead"
, write_time/writes "SecsPerWrite"
from v$asm_disk_stat
where header_status not in ('FORMER','CANDIDATE','PROVISIONED')
order by group_number
, disk_number
/
------------------------------------------------------
ASM - File Types in Diskgroups
-----------------------------------------------
Prompt File Types in Diskgroups
Prompt ========================
col "File Type" for a16
col "Block Size" for a5 Head "Block|Size"
col "Gb" for 9990.00
col "Files" for 99990
break on "Group Name" skip 1 nodup
select g.name "Group Name"
, f.TYPE "File Type"
, f.BLOCK_SIZE/1024||'k' "Block Size"
, f.STRIPED
, count(*) "Files"
, round(sum(f.BYTES)/(1024*1024*1024),2) "Gb"
from v$asm_file f,v$asm_diskgroup g
where f.group_number=g.group_number
group by g.name,f.TYPE,f.BLOCK_SIZE,f.STRIPED
order by 1,2;
------------------------------------------------------
ASM - Instances currently accessing these diskgroups
------------------------------------------------------
prompt Instances currently accessing these diskgroups
prompt ==============================================
col "Instance" form a8
select c.group_number "Group"
, g.name "Group Name"
, c.instance_name "Instance"
from v$asm_client c
, v$asm_diskgroup g
where g.group_number=c.group_number
------------------------------------------------------
ASM - Assigned ASM disks and their paths
------------------------------------------------------
prompt Assigned ASM disks and their paths
prompt ==============================
col "Disk Size" form a9
select header_status "Header"
, mode_status "Mode"
, path "Path"
, lpad(round(os_mb/1024),7)||'Gb' "Disk Size"
from v$asm_disk
where header_status in ('MEMBER')
order by path
------------------------------------------------------
ASM - Free ASM disks and their paths
------------------------------------------------------
prompt Free ASM disks and their paths
prompt ==============================
col "Disk Size" form a9
select header_status "Header"
, mode_status "Mode"
, path "Path"
, lpad(round(os_mb/1024),7)||'Gb' "Disk Size"
from v$asm_disk
where header_status in ('PROVISIONED','FORMER')
order by path
/
------------------------------------------------------
ASM - ASM disks and their paths
------------------------------------------------------
prompt ASM disks and their paths
prompt ==============================
col "Disk Size" form a9
select header_status "Header"
, mode_status "Mode"
, path "Path"
, lpad(round(os_mb/1024),7)||'Gb' "Disk Size"
from v$asm_disk
where header_status in ('MEMBER','PROVISIONED','CANDIDATE','FORMER')
order by path
/
------------------------------------------------------
ASM - Current ASM disk operations
------------------------------------------------------
prompt Current ASM disk operations
prompt ===========================
select *
from v$asm_operation
/
views
-----
v$asm_operation
v$asm_disks
v$asm_diskgroups
v$asm_file
v$asm_client
v$asm_disk_stats
-- Check ASM diskgroup built on raw devices
set pages 50000 lines 120
col path for a15
select a.path,b.NAME from v$asm_disk a, v$asm_diskgroup b
where a.GROUP_NUMBER=b.GROUP_NUMBER and
a.path like '%raw%' ;
--check how the different disks of the diskgroups are utilized
select
instname,
dbname,
group_number,
failgroup,
disk_number,
reads,
writes
from v$asm_disk_iostat
order by 1,2,3,4,5,6
/
set pages 50000 lines 120
col path for a30
select disk_number,
mount_status,
header_status,
mode_status,
state,path
from v$asm_disk ;
set pages 50000 lines 120
select path,redundancy,total_mb,free_mb,failgroup from v$asm_disk where mount_status='CACHED' and header_status='MEMBER' and mode_status='ONLINE' and state='NORMAL'order by path;
Note : to mount diskgroup - use
sql>alter diskgroup all mount;
or specific diskgroup.
list from v$asm_diskgroup(name,state)
then
sql>alter diskgroup DATA mount;
Note: For ASM Instance , Will start and mount the diskgroups.
No DB will open or there in ASM.
gv$instance (instance_name,status)
using asmca - asm configuration assistant
To create diskgroup/adding/removing disks.
#xhost +
$su - oracle
$. grid_env
$asmca
Click on tab ( disk group)
-> Create/mount/dismount
Diskgroup Name : FRA
External
Choose - Disk2
AU - 4
Versions - 11.2.0.0.0
Ok
-? Adding disks :
righ click on diskgroup
then
choose - add disk.
Note : in FRA - fast recovery area
holds - backup sets,redo,control
archivelogs.
oracle recommends to manage with min two asm diskgroups.
DATA - to hold datafiles
FRA -
For every diskgroup , recommend with min 4 disks
for better performance with best practice.
with Allocation Unit (AU) - 4mb(best)
is a fundamental unit in which contiguous disk space is
allocated to asm files.
default - 1 , can have 2,4,8,16,32,64
To dismount - Diskgroups
-----------------------------
right click - dismount on local node
or
Dismount on all nodes
Dropping a diskgroup
-------------------------
right click - drop diskgroup
Creating Diskgroup
------------------
sql>CREATE DISKGROUP fra EXTERNAL REDUNDANCY DISK 'ORCL:DISK2';
sql>select name,state from v$asm_diskgroup;
SQL> alter diskgroup FRA dismount;
sql>select name,state from v$asm_diskgroup;
SQL> alter diskgroup FRA mount;
sql>select name,state from v$asm_diskgroup;
SQL> DROP DISKGROUP FRA INCLUDING CONTENTS;
Mounting/Unmounting disk group.
--------------------
SQL>alter diskgroup FRA mount;
SQL>alter diskgroup FRA dismount;
sql>alter diskgroup all mount;
sql>alter diskgroup all dismount;
Dropping Diskgroup:
-------------------------
SQL> DROP DISKGROUP FRA INCLUDING CONTENTS;
Add Disk 2
--------------
sql>CREATE DISKGROUP OCRvote EXTERNAL REDUNDANCY DISK 'ORCL:DISK2';
sql>ALTER DISKGROUP DATA ADD DISK 'ORCL:DISK2';
sql>select * from v$asm_operation; (on another terminal - monitor)
-- Drop a disk. if two disks are there
sql>ALTER DISKGROUP DATA DROP DISK DISK2;
sql>select * from v$asm_operation;
With wait - using runtime rebalance
--------------------------------
ALTER DISKGROUP DATA ADD DISK
'ORCL:DISK2'
REBALANCE POWER 2 WAIT;
How to check consistency for metadata for all disks ?
ALTER DISKGROUP DATA CHECK ALL;
Drop Diskgroup using force.
---------------------------
If unable to mount ,use force
SQL> DROP DISKGROUP OCRVOTE FORCE;
ALTER DISKGROUP DATA ADD DISK
'/devices/diska5' NAME diska5,
'/devices/diska6' NAME diska6,
'/devices/diska7' NAME diska7,
'/devices/diska8' NAME diska8;
=========================================
Creating of Diskgroup with Normal redundancy
CREATE DISKGROUP DATA NORMAL REDUNDANCY
FAILGROUP fg1 DISK '/devices/diskg1'
FAILGROUP fg2 DISK '/devices/diskg2'
QUORUM FAILGROUP fg3 DISK '/devices/diskg3'
ATTRIBUTE 'compatible.asm' = '11.2.0.0.0';
ALTER DISKGROUP data1 ADD DISK
'/devices/diskd*'
REBALANCE POWER 5 WAIT;
Explain With or with out rebalance operation while adding disk?
With out -
With option - then it runs with rebalance 5 and does not return until the rebalance operation is complete.
----------------------------------------------------------
The size support by Type of redundancy
Each Diskgroup supports - size.
------------------------------
External - Supports up to 140PB from 11.1
till 10.1 - 16TB
Normal - 11.1 -? 23PB
10.1 -? 5.8TB
High - 11.1 -? 15PB
10.1 -? 3.9TB
ASM_POwer_limit supports up to 1024
--------------------------------------------------
ASM Commands - interactive mode.
-----------
$asmcmd
chdg Changes a disk group (add, drop, or rebalance).
chkdg Checks or repairs a disk group.
dropdg Drops a disk group.
iostat - Displays I/O statistics for disks.
lsattr - Lists the attributes of a disk group.
lsdg - Lists disk groups and their information.
lsdsk - Lists disks Oracle ASM disks.
lsod - Lists open devices.
md_backup - Creates a backup of the metadata of mounted disk groups.
md_restore - Restores disk groups from a backup of the metadata.
mkdg - Creates a disk group.
mount - Mounts a disk group.
The attribute can be set with SQL, ASMCMD, or ASMCA.
Brief few views to find information in ASM
v$asm_disk - Disk Utilization
v$asm_diskgroup
v$asm_client
v$asm_file
v$asm_disk_stat
v$asm_operation - For finding rebalacing status while add/remove disks
Tasks - ASM
-----------
Adding Diskgroup
Adding Disk to a Diskgroup
Dropping Disk
Dropping Diskgroup
Monitoring rebalancing operation
mounting/dismounting - diskgroups
ASM Instance - start/stop/status - using srvctl / sqlplus
Oracle recommends to manage with min two diskgroups.
DATA - to store datafiles,spfile,ocr/voting. ( while cluster install)
FRA - to store controlfiles,redo,archives,backupsets
OCRVOTE - to store ocr/vote if multiplexing.
asmca
asmcmd
Changing parameter in cluster nodes
use sid='*' to effect/change in all nodes of a cluster.
NON ASM to ASM
RAC Files
----------------------------------
For Deinstalling - DB
Bring up cluster on all nodes - verify status
su - oracle
. db_env
cd $ORACLE_HOME/deinstall
./deinstall
Accept the inputs...done.
---------------------------------
NOn asm - to ASM
deinstall Database
Bring down cluster services,crs
On rac1 ,
su - oracle
. db_env
/database/
./runInstaller
here choose file system(not asm)
dbname - prod
/oradata
sqlplus '/as sysdba'
shutdown immediate
----------------------------
ASM
instance
. grid_env
export ORACLE_HOME=/u01/app/11.2.0/grid/bin
export ORACLE_SID=+ASM1
Tools
----
asmca - configuration assistant - create diskgroups/drop / add disks/drop disks/mount/unmount
asmcmd - command line interpreter to manage files/diskgroups
ASM Views - brief information of ASM file/disks/diskgroups/status
----------------------------------------------------------
v$asm_file
v$asm_diskgroups
V$asm_disks
v$asm_operation
v$asm_disk_stat
v$asm_client
ASM - Tasks
Monitor the usage of the diskgroup
Allocate disks to the diskgroup
Monitor rebalancing activity when disk was added/removed
List of diskgroups
list of files in diskgroup and its usage
diskgroup status - mounted/unmounted/online
Disks Provisioned/former/member - online/offline - status
Note: info on oracle ASM it my be differ from your environment production,development,testing
THANKS FOR VIEWING MY BLOG FOR MORE UPDATES FOLLOW ME
