Exadata Basic info :
EHCC - Exadata Hybrid Columnar Compression
CU - Compression Unit
PDU - Power Distribution Unit
IB - InfiniBand
ILOM - Integrated Lights Out Manager
IPMI - Intelligent Platform Management Interface
LUN - Logical Unit Number
HARD - Hardware Assisted Resilient Data
RDS - Reliable Data Socket protocol
iDB - Intelligent Database protocol
UDMs - User Defined Metrics
IOPS - IOs Per Second
OEL - Oracle Enterprise Linux
SNMP - Simple Network Management Protocol
MS - Management Server
RS - Restart Server
EM - Enterprise Manager
EMGC - Enterprise Manager Grid Control
HCA - Host Controller Adapter
HBA - Host Bus Adapter
SM - Subnet Manager
DBRM - Database Resource Manager
SATA - Serial Advanced Technology Attachment
SAS - Serial Attached SCSI
Oracle Exadata Full Half Quarter Racks differences
Here are some differences between Full Rack, Half Rack and Quarter Racks
(in Oracle Exadata).
I consider the following seven terms and definitions utterly important for folks to know before sitting through an Exadata presentation.
Cell Offload Processing.
Work performed by the Storage Servers that would otherwise have to be executed in the database grid. Includes functionality like Smart Scan, datafile initialization, RMAN offload, Hybrid Columnar Compression (HCC) decompression.
Smart Scan.
Most relevant Cell Offload Processing for improving Data Warehouse / Business Intelligence query performance. Smart Scan is the agent for offloading filtration, projection, Storage Index exploitation and HCC decompression.
Full Scan or Index Fast Full Scan.
The required access method chosen by the query optimizer in order to trigger a Smart Scan.
Direct Path Reads.
Required buffering model for a Smart Scan. The flow of data from a Smart Scan cannot be buffered in the SGA buffer pool. Direct path reads can be performed for both serial and parallel queries. Direct path reads are buffered in process PGA (heap).
Result Set.
Data returned by the SQL processing layer. The SQL processing layer is in the Oracle Database. The data flowing from a Smart Scan is not a result set.
Exadata Smart Flash Cache.
Flash Cache in each of the Storage Servers. Not to be confused with Database Flash Cache which is Flash in the database grid and not compatible with Exadata. Smart Scan aggressively scans both HDD and Flash media concurrently. When data is present in the flash cache scan rates of 50 GB/s on Exadata Version 2 hardware are the norm for full rack configurations. Maximum theoretical scan rates (a.k.a., datasheet scan rates) for Exadata are *only* possible for fully offloaded scans. A fully offloaded scan is generated by a SQL query that finds no rows.
Storage Index.
Dynamic, in-memory indexes. The role of Storage Index technology is not to aid in locating data faster but instead to eliminate I/O. With Storage Indexes the Exadata Storage Server software can determine whether or not a given storage region contains rows relevant to the query and decide to not read the storage region. Storage Indexes are only examined during a Smart Scan.
I hope you’ll find this helpful.
EHCC - Exadata Hybrid Columnar Compression
CU - Compression Unit
PDU - Power Distribution Unit
IB - InfiniBand
ILOM - Integrated Lights Out Manager
IPMI - Intelligent Platform Management Interface
LUN - Logical Unit Number
HARD - Hardware Assisted Resilient Data
RDS - Reliable Data Socket protocol
iDB - Intelligent Database protocol
UDMs - User Defined Metrics
IOPS - IOs Per Second
OEL - Oracle Enterprise Linux
SNMP - Simple Network Management Protocol
MS - Management Server
RS - Restart Server
EM - Enterprise Manager
EMGC - Enterprise Manager Grid Control
HCA - Host Controller Adapter
HBA - Host Bus Adapter
SM - Subnet Manager
DBRM - Database Resource Manager
SATA - Serial Advanced Technology Attachment
SAS - Serial Attached SCSI
Oracle Exadata Full Half Quarter Racks differences
Here are some differences between Full Rack, Half Rack and Quarter Racks
(in Oracle Exadata).
| RACK | No. of Cells | No. of Nodes | No. of Cores | No. of Disks | SAS Storage | SATA Storage | No. of InfiniBand Switches |
| Full Rack | 14 Cells | 8 Nodes |
64
|
168
|
100TB
|
336TB
|
3
|
| Half Rack | 7 Cells | 4 Nodes |
32
|
84
|
50TB
|
168TB
|
3
|
| Quarter Rack | 3 Cells | 2 Nodes |
16
|
36
|
21TB
|
72TB
|
2
|
I consider the following seven terms and definitions utterly important for folks to know before sitting through an Exadata presentation.
Cell Offload Processing.
Work performed by the Storage Servers that would otherwise have to be executed in the database grid. Includes functionality like Smart Scan, datafile initialization, RMAN offload, Hybrid Columnar Compression (HCC) decompression.
Smart Scan.
Most relevant Cell Offload Processing for improving Data Warehouse / Business Intelligence query performance. Smart Scan is the agent for offloading filtration, projection, Storage Index exploitation and HCC decompression.
Full Scan or Index Fast Full Scan.
The required access method chosen by the query optimizer in order to trigger a Smart Scan.
Direct Path Reads.
Required buffering model for a Smart Scan. The flow of data from a Smart Scan cannot be buffered in the SGA buffer pool. Direct path reads can be performed for both serial and parallel queries. Direct path reads are buffered in process PGA (heap).
Result Set.
Data returned by the SQL processing layer. The SQL processing layer is in the Oracle Database. The data flowing from a Smart Scan is not a result set.
Exadata Smart Flash Cache.
Flash Cache in each of the Storage Servers. Not to be confused with Database Flash Cache which is Flash in the database grid and not compatible with Exadata. Smart Scan aggressively scans both HDD and Flash media concurrently. When data is present in the flash cache scan rates of 50 GB/s on Exadata Version 2 hardware are the norm for full rack configurations. Maximum theoretical scan rates (a.k.a., datasheet scan rates) for Exadata are *only* possible for fully offloaded scans. A fully offloaded scan is generated by a SQL query that finds no rows.
Storage Index.
Dynamic, in-memory indexes. The role of Storage Index technology is not to aid in locating data faster but instead to eliminate I/O. With Storage Indexes the Exadata Storage Server software can determine whether or not a given storage region contains rows relevant to the query and decide to not read the storage region. Storage Indexes are only examined during a Smart Scan.
I hope you’ll find this helpful.
