©OraInternals Riyaj Shamsudeen
 ART: ASM
By Riyaj Shamsudeen
 
©OraInternals Riyaj Shamsudeen
2
 Architecture: With ASM
Prod1
SAN switchPrivate network switchNon-routeablenetwork For interconnect
Sol1 ASM1
 
IO path
Prod2Sol2 ASM2
 
IO path
Prod3Sol3 ASM3
 
IO path
 
©OraInternals Riyaj Shamsudeen
3
 ASM & RDBMS
 ASM manages disk groups and disks; provides a physical block access to the RDBMS instances.
RDBMS instance(s) performs conventional read and write calls to the database files and ASM is not involved.
It is a common misconception that ASM participates in conventional I/O activity.
Only during file metadata operations, such file creation, deletion etc, ASM is involved.
 
©OraInternals Riyaj Shamsudeen
4
RDBMS is a client
RDBMS instance connects to ASM instance as a foreground connection.
asmbprocess running in RDBMS instance makes a connection to ASM instance.
 Asmbprocess acts as a conduit between database and ASM.  Asmbprocess also acts as a method to detect ASM crash.
If ASM instance crashes, asmbconnection will die leading to an instance crash.
Demo: asm_connections.sql, asm_clients.sql
of 35