Archive for the ‘Fibre Channel’ Category

IO Stack [PIC]

Tuesday, January 22nd, 2008

I/O stack components Overview Typically the stack consists of the following • Database • Character or block device driver • Multipathing driver • SCSI driver • HBA • System Bus • Switch/iSCSI routers • Storage Array • Disks Example of vendors: ASM-Database IBM Oracle Character or block device driver Multipathing driver – PowerPath, Windows MPIO SCSI driver HBA – Host Bus Adapter, Qlogic (IBM), Emulex System Bus ...

2 Gigabit Card - How fast is it?

Tuesday, January 22nd, 2008

Common misunderstandings: “If I buy 2 Gigabit HBAs I will get 2 Gigabytes of throughput, that’s more than enough throughput for my 400 MB/s application” “I only need 2 disks to store my 1 TB database, now that we have 500GB disk drives are available!” The first misunderstanding is not just about bits ...

Performance Definition: throughput

Tuesday, January 22nd, 2008

Saw this definition from one of the Oracle OpenWorld sessions, thought it was pretty clear and concise: Throughput The measure of the transfer of bits across the media over a given period of time. Commonly used in discussing data transfer rates Due to a number of factors, throughput usually does not match the ...