Tidbit:Oracle:Exadata:Flash Disks Information

Use below commands to get information on Exadata Cell Flash Disks

CellCLI> list celldisk where diskType = FlashDisk

         FD_00_cell      normal
         FD_01_cell      normal
         FD_02_cell      normal
         FD_03_cell      normal

CellCLI> list celldisk where diskType = FlashDisk DETAIL

         name:                   FD_00_cell
         comment:
         creationTime:           2010-10-21T14:52:28-07:00
         deviceName:             /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH01
         devicePartition:        /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH01
         diskType:               FlashDisk
         errorCount:             0
         freeSpace:              0
         id:                     0000012b-d0c7-42f2-0000-000000000000
         interleaving:           none
         lun:                    /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH01
         raidLevel:              "RAID 0"
         size:                   496M
         status:                 normal


         name:                   FD_01_cell
         comment:
         creationTime:           2010-10-21T14:52:30-07:00
         deviceName:             /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH02
         devicePartition:        /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH02
         diskType:               FlashDisk
         errorCount:             0
         freeSpace:              0
         id:                     0000012b-d0c7-61d3-0000-000000000000
         interleaving:           none
         lun:                    /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH02
         raidLevel:              "RAID 0"
         size:                   496M
         status:                 normal


         name:                   FD_02_cell
         comment:
         creationTime:           2010-10-21T14:52:31-07:00
         deviceName:             /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH03
         devicePartition:        /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH03
         diskType:               FlashDisk
         errorCount:             0
         freeSpace:              0
         id:                     0000012b-d0c7-695e-0000-000000000000
         interleaving:           none
         lun:                    /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH03
         raidLevel:              "RAID 0"
         size:                   496M
         status:                 normal


         name:                   FD_03_cell
         comment:
         creationTime:           2010-10-21T14:52:32-07:00
         deviceName:             /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH04
         devicePartition:        /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH04
         diskType:               FlashDisk
         errorCount:             0
         freeSpace:              0
         id:                     0000012b-d0c7-6cdc-0000-000000000000
         interleaving:           none
         lun:                    /opt/oracle/cell11.2.2.1.0_LINUX_101005/disks/raw/FLASH04
         raidLevel:              "RAID 0"
         size:                   496M
         status:                 normal

Books: Exadata Books Coming!

Looks like couple oracle exadata books are in cooking already!

Achieving Extreme Performance with Oracle Exadata (Osborne ORACLE Press Series)


Expert Oracle Exadata



              

Exadata Performance Monitoring Part 1

CELLCLI LIST command can be used to monitor and monitor cell performance metrics

To receive some help on specific performance metric, use

list metricdefinition <metric_name> DETAIL

For Example:

CellCLI> list metricdefinition Io_LOAD DETAIL
         name:                   IO_LOAD
         description:            "Average I/O load for hard disks"
         metricType:             Instantaneous
         objectType:             CELL
         unit:                   Number

To display specific metric value, use:

CellCLI> LIST METRICCURRENT CL_CPUT DETAIL
         name:                   CL_CPUT
         alertState:             normal
         collectionTime:         2011-02-17T00:39:32-08:00
         metricObjectName:       cell
         metricType:             Instantaneous
         metricValue:            30.6 %
         objectType:             CELL
LIST command also accepts where clause (attribute filters):

To Show all immediate non-zero performance metric values:

LIST METRICCURRENT where metricValue > 0

CD_IO_TM_R_LG   CD_disk02_cell                                  36,321 us
CD_IO_TM_R_SM   CD_disk01_cell                                  1,347,527 us
CD_IO_TM_R_SM   CD_disk02_cell                                  1,151,048 us
CD_IO_TM_R_SM   CD_disk03_cell                                  931,721 us
CD_IO_TM_R_SM   CD_disk04_cell                                  2,286,866 us
CD_IO_TM_R_SM   CD_disk05_cell                                  958,574 us

To show historical data, use LIST METRICHISTORY Command:

You can use metricobjectname to show specific disk and collectiontime to show specific timeframe.

Make sure to filter data as default "list metrichistory" would provide too much data to comprehend

CellCLI> list metrichistory CD_IO_RQ_W_SM where metricobjectname = CD_disk01_cell and collectiontime > '2011-02-17T00:53:01-08:00' and metricvalue > 0

CD_IO_RQ_W_SM   CD_disk01_cell  350,071 IO requests  2011-02-17T00:53:19-08:00
CD_IO_RQ_W_SM   CD_disk01_cell  356,091 IO requests  2011-02-17T00:54:19-08:00
CD_IO_RQ_W_SM   CD_disk01_cell  358,111 IO requests  2011-02-17T00:55:19-08:00
CD_IO_RQ_W_SM   CD_disk01_cell  381,131 IO requests  2011-02-17T00:56:19-08:00
CD_IO_RQ_W_SM   CD_disk01_cell  454,151 IO requests  2011-02-17T00:57:19-08:00
CD_IO_RQ_W_SM   CD_disk01_cell  470,171 IO requests  2011-02-17T00:58:19-08:00
CD_IO_RQ_W_SM   CD_disk01_cell  640,191 IO requests  2011-02-17T00:59:20-08:00
CD_IO_RQ_W_SM   CD_disk01_cell  850,211 IO requests  2011-02-17T01:00:20-08:00

tidbit:Oracle:Exadata Wait Events (cell related)

Exadata Wait Events:

NAME                                                             WAIT_CLASS
---------------------------------------------------------------- --------------------------------------------------

cell list of blocks physical read                                User I/O
cell manager cancel work request                                 Other
cell manager closing cell                                        System I/O
cell manager discovering disks                                   System I/O
cell manager opening cell                                        System I/O
cell multiblock physical read                                    User I/O
cell single block physical read                                  User I/O
cell smart file creation                                         User I/O
cell smart flash unkeep                                          Other
cell smart incremental backup                                    System I/O
cell smart index scan                                            User I/O
cell smart restore from backup                                   System I/O
cell smart table scan                                            User I/O
cell statistics gather                                           User I/O
cell worker idle                                                 Idle
cell worker online completion                                    Other
cell worker retry                                                Other

tidbit:Oracle:Exadata System Statistics (cell related)

Exadata cell statistics:

STATISTIC# NAME                                                                  CLASS
---------- ---------------------------------------------------------------- ----------
        51 cell physical IO interconnect bytes                                      64
       224 cell physical IO bytes saved during optimized file creation              64
       225 cell physical IO bytes saved during optimized RMAN file restore          64
       226 cell physical IO bytes eligible for predicate offload                    64
       227 cell physical IO bytes saved by storage index                             8
       228 cell smart IO session cache lookups                                      64
       229 cell smart IO session cache hits                                         64
       230 cell smart IO session cache soft misses                                  64
       231 cell smart IO session cache hard misses                                  64
       232 cell smart IO session cache hwm                                          64
       233 cell num smart IO sessions in rdbms block IO due to user                 64
       234 cell num smart IO sessions in rdbms block IO due to big payload          64
       235 cell num smart IO sessions using passthru mode due to user               64
       236 cell num smart IO sessions using passthru mode due to cellsrv            64
       237 cell num smart IO sessions using passthru mode due to timezone           64
       238 cell num smart file creation sessions using rdbms block IO mode          64
       239 cell physical IO interconnect bytes returned by smart scan               64
       240 cell session smart scan efficiency                                       64
       359 cell scans                                                               64
       360 cell blocks processed by cache layer                                    128
       361 cell blocks processed by txn layer                                      128
       362 cell blocks processed by data layer                                     128
       363 cell blocks processed by index layer                                    128
       364 cell commit cache queries                                                64
       365 cell transactions found in commit cache                                  64
       366 cell blocks helped by commit cache                                       64
       367 cell blocks helped by minscn optimization                                64
       368 cell blocks skipped due to chained rows                                  64
       369 cell simulated physical IO bytes eligible for predicate offload         192
       370 cell simulated physical IO bytes returned by predicate offload          192
       371 cell simulated session smart scan efficiency                            192
       372 cell CUs sent uncompressed                                               64
       373 cell CUs sent compressed                                                 64
       374 cell CUs sent head piece                                                 64
       375 cell CUs processed for uncompressed                                      64
       376 cell CUs processed for compressed                                        64
       377 cell IO uncompressed bytes                                               64
       394 cell index scans                                                         64
       571 cell flash cache read hits                                                8

Re: Exadata Oracle performance troubleshooting

Just stumbled upon a great article related to Oracle problem troubleshooting on Exadata:

Issue is related to "TABLE ACCESS STORAGE FULL" in exec plan (smart scans) and tables with the very large number of columns, which is typical for any serious production environment.

See below:

http://tech.e2sn.com/oracle/exadata/performance-troubleshooting/exadata-smart-scan-performance