Jan-14

24-Jan

ASM and Exadata

http://asmsupportguy.blogspot.in/2012/04/asm-in-exadata.html

Grid disks are not seen by operating System, rather only Oracle ASM can see the Grid disks via oracle proprietary protocol iDB.

Kfod : Grid disk discovery tools.

$ kfod disks =all    è To list all Grid disks

CELL commands

http://www.oracle.com/technetwork/articles/oem/exadata-commands-part3-402445.html

http://www.oracle.com/technetwork/articles/oem/exadata-commands-intro-402431.html

21-Jan

To create a grid disk in all HARDDISKs


Cellcli> create griddisk all harddisk prefix=’DATA’ size 200M;

To create a grid disk on a specific hard disk


Cellcli> create griddisk DATA_DG_CD_00cell01 celldisk=’CD_00_cell01’, size 200m

Grid disks and its attributes can be listed


Cellcli> list griddisk attributes name,celldisk, disktype, size

Create a flash grid disk


Cellcli> create  griddisk all flashdisk prefix=’FLASHDISK’

20-Jan

Apache Cassandra tutorials

http://www.datastax.com/resources/tutorials

ILOM:   Exadata ILOM (Integrated Lights Out Manager) is an adaptor card in addition to the management network interface (NET0) in each storage server and database server.   ILOM boots as soon as the server power is up and operates independently of OS allowing web and SSh access.  The ILOM allows the DBA to perform many management tasks remotely otherwise require physical access to the server including Console access, power up, power down systems, re-booting servers etc.  ILOM is capable to monitor the H/W functioning and report if there is a failure.  ILOM is linked to the management switch using a Ethernet port.

Oracle Exadata documentation is available at /usr/share/doc/oracle/Exadata in all storage servers and not available publically.

To list all CELL physical disks


Cellcli –e list physicaldisk

Shutdown /startup all cell services


Cellcli> alter cell shutdown services all;

Cellcli> alter cell startup services all;

16-Jan

Transaction guard – oracle 12c

http://www.oracle.com/technetwork/database/database-cloud/private/transaction-guard-wp-12c-1966209.pdf

Oracle 12c – Application continuity

http://www.oracle.com/technetwork/database/options/clustering/ac-overview-1967264.html

Some x$ table references..

http://yong321.freeshell.org/computer/x$table.html

x$ tables – from where do they comes from

http://blog.tanelpoder.com/2014/01/10/oracle-x-tables-part-1-where-do-they-get-their-data-from/?utm_source=rss&utm_medium=rss&utm_campaign=oracle-x-tables-part-1-where-do-they-get-their-data-from

Playing with baseline

http://oracleprof.blogspot.in/2011/07/how-to-find-sqlid-and-planhashvalue-in.html

10-Jan

In oracle 11g onwards, tracing 10046 is enhanced.  You can trace a OS level process by


SQL> ALTER SESSION SET EVENTS 'SQL_TRACE {PROCESS:5729} ';

Session altered.

SQL> ALTER SESSION SET EVENTS 'SQL_TRACE {PROCESS:5729} OFF' ;

Session altered.

Where 5729 is an OS level process identifier.

You can also trace 10046 level for a specific SQL using SQL_ID


SQL>  alter session set events 'sql_trace [SQL:5m6mu5pd9w028] off ' ;

Session altered.

You can also concatenate multiple SQLs trace in single event.


SQL> alter session set events 'sql_trace  [sql:5m6mu5pd9w028|1fkh93md0802n] ' ;

Session altered.

Using a Oracle process ID you can trace a session


SQL> select paddr from v$session where username='THOMAS' ;

PADDR

----------------

00000000EC503F20

SQL> select pid from v$process  where addr='00000000EC503F20';

PID

----------

28

SQL> alter session set events 'sql_trace {process:orapid=28 }' ;

Session altered.

SQL>  alter session set events 'sql_trace {process:orapid=28 } off';

Session altered.

Use pname to trace session  as,


SQL> alter session set events 'sql_trace {process:pname=PMON} ' ;

Session altered.

SQL> alter session set events 'sql_trace {process:pname=PMON} off ';

Session altered.

You can also specify to capture waits and binds


SQL> alter session set events 'sql_trace {process:pname=PMON} wait=true,bind=true,level=12';

Session altered.

09-Jan

Flash Cache can be created and listed using CELCLI command.  First create cell disks in the PCI flash devices


CELLLCLI> create celldisk all flashdisk

To list all the cell disks


CELLCLI> LIST CELLDISK ATTRIBUTES name, disktype, size where name like ‘FD.*’;

To create a smart flash cache in all Cell disks


CELLCLI> CREATE FLASHCACHE ALL

To create flash cache on selected Cell Disks and size


CELLCLI> create flashcache celldisk =’cell_disk_1, cell_disk_2, cell_disk_3.. ‘, size 30G

To list out the flash cache details


CELLCLI> list flashcache detail

In each storage node there are 4 PCI solid state flash modules (Fmods –  F20 cards) each sizing 32GB, but 22.875 GB usable storage.  Each Fmods contain 64MB controller Ram (volatile) memory and eight 4GB SLC NAND components.    The 64MB RAM is powered by a ESM (Energy Storage Module) using a capacitor to avoid data corruption by sudden power loss.   This 64MB controller RAM buffers the data writes to the Flash module and will write directly to the SLC NAND if ESM is not functional which will cause reduced I/O performance. The IOLM (Integrated Lights Out manager) module monitors the ESM and send warnings if there are any issues


CellCLI> LIST CELLDISK ATTRIBUTES name, disktype, size where name like 'FD.*';

FD_00_ct01cel01         FlashDisk       22.875G

FD_01_ct01cel01         FlashDisk       22.875G

FD_02_ct01cel01         FlashDisk       22.875G

FD_03_ct01cel01         FlashDisk       22.875G

FD_04_ct01cel01         FlashDisk       22.875G

FD_05_ct01cel01         FlashDisk       22.875G

FD_06_ct01cel01         FlashDisk       22.875G

FD_07_ct01cel01         FlashDisk       22.875G

FD_08_ct01cel01         FlashDisk       22.875G

FD_09_ct01cel01         FlashDisk       22.875G

FD_10_ct01cel01         FlashDisk       22.875G

FD_11_ct01cel01         FlashDisk       22.875G

FD_12_ct01cel01         FlashDisk       22.875G

FD_13_ct01cel01         FlashDisk       22.875G

FD_14_ct01cel01         FlashDisk       22.875G

FD_15_ct01cel01         FlashDisk       22.875G

Smart flash cache read statistics are available in V$SYSSTAT under “CELL FLASH CACHE READ HITS”.

The PCI Flash memory can be used in two ways – as intermediate cache to store data (Smart Flash Cache) to speed up the random access reads or define as SSD (Solid State Disks) under ASM to store the database files.

With write back flash cache feature, the Exadata smart flash cache buffers database blocks writes.    Write caching eliminates disk bottlenecks in large OLTP systems and get constant write I/O performance.  The Exadata write cache is transparent, persistent and fully redundant.

Exadata smart flash cache logging feature helps to reduce log I/O latency issues.   Exadata flash ache logging combined with high speed disk controllers helps to fast response to a committing session completing the transaction faster.

You can use any of the flowing syntax based on the requirement.


CELLCLI> CREATE FALSHLOG ALL

CELLCLI> CREATE FALSHLOG ALL SIZE  = 1G

CELLCLI> CRAETE FALSHLOG CELDISK=’<disk1>,<disk2>…. <disk n>’

CELCLI>  CRAETE FALSHLOG CELDISK=’<disk1>,<disk2>…. <disk n>’  SIZE =1G

You can get information about flash logging using,

[ode]

CELLCLI> LIST FALSHLOG [attributes] DETAIL

CELLCLI> LIST FLASHLOG

CELLCLI> LIST FLASHLOG DETALS

[/code]

You can get cell storage level (individual cell storage) metric statistics querying


CELLCLI> LIST METRICDEFINITON attributes name, description where OBEJCTYPE=’FLASHCACHE’

CELLCLI> LIST METRICCURRENT where objecttype=’FLASHCACHE’

You can list the number ESFC  content by querying,


CELLCLI> LIST FLASHCACHECONTENT WHERE dbuniquename=’<name>’ ATTRIBUTES <attr1, attr2.. attrn>’

You can list the attributes by

 CELLCLI> describe flashcachecontent

07-Jan

Exadata Smart Flash Cache:  Is ultra performance Flash Cache built on PCI flash cards directly attached to the high speed PCI bus.    The Exadata smart flash cache automatically caches frequently accessed data in the flash cache.   In addition to automatic caching, DBA can specify to cache tables and indexes explicitly.   The table creation option KEEP will place the object in the cache while NONE will avoid using cache and DEFAULT will leads oracle to take a decision to cache the data or not.  You can check the object status in cache using


Cellcli>  list flashcachecontent where object_number  = <object_id> details;

To list value of CacheKeepSize


Celcli –e list flashcachecontent  attributes dbuniquename, objectnumber, cachedkeepsize,  cachedsize, hitcount, misscount;

You can enable object level caching using


ALTER TABLE <table name> STORAGE  (CELL_FLASH_CACHE  KEEP/DEFAULT/NONE;

You can get the TABLE / INDEX level caching enabled by querying – DBA_TABLES/DBA_INDEXES


SQL> SELECT table_name, cell_flash_cache FROM DBA_TABLES;

06-Jan

While ADDing EXTRACT in a RAC environment, you should specify the number of THREADS in the RAC environment.

[Code]

GGSCI> ADD EXTRACT  myext, TRANLOG, THREADS 2, BEGIN NOW

[/code]

While the REDO/ARCH files are in ASM environment, extract need to be configured access the ASM instance and can be done using TRANLOG OPTIONS.  To configure ASM environment for extract,


TRANLOGOPTIONS ASMUSER  “sys@asmdb”,  ASMPASSWORD  “<encrypted password> “

ENCRYPTKEY default

Use ARCHIVEDLOGFORMATS with TRANLOGOPTIONS to configure alternate location for archive logs for GG.    You can configure multiple archive log locations; so that the extract will continue to mine even if the archive log files are moved to non-default secondary location.   PRIMARY keyword will skip the DEFAULT log location and will look for log files in the specified path.


TRANLOGOPTIONS ALTARCHIVELOGDEST PRIMARY INSTANCE rac1 /disk1/node1/arch,

ALTARCHIVELOGDEST INSTANCE rac1 /disk2/node1/arch,

ALTARCHIVELOGDEST INSTANCE rac2 /disk1/node2/arch

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