1: iSCSI compared to DAS and FC SAN. 

Contexts in source publication

Context 1

... SAN protocol over TCP/IP is the so called Internet SCSI (iSCSI). As a NAS protocol we will discuss the NFS protocol in its latest release, which provides special enhancements for working better over existing internet infrastructures. In The We this conclude SAN chapter protocol this we chapter will over look TCP/IP by at further concrete is the comparing so distributed called these Internet storage protocols SCSI protocols (iSCSI). and evalu- which As are a ating NAS specified the protocol performance to work we will over of discuss NAS existing and the TCP/IP NFS SAN protocol based networks. protocols. in its latest release, which provides special enhancements for working better over existing internet infrastructures. We conclude this chapter by further comparing these protocols and evalu- ating the performance of NAS and SAN based protocols. Being a typical SAN protocol, it works on blocks (physical addressing). An iSCSI client is called an initiator and an iSCSI storage device is called a target. Instead of a HBA the iSCSI initiator uses an ordinary Network Interface Card (NIC). The iSCSI initiator communicates with a storage router or gateway, which knows how to map the iSCSI commands to physical storage. Internet Being Instead As can a be of typical SCSI a seen HBA (iSCSI) SAN in the figure 5.1, protocol, is iSCSI a SAN initiator iSCSI it technology works uses uses on existing blocks with an ordinary a (physical special network Network focus addressing). infrastructures. on Interface existing An infrastructure. iSCSI Card Instead (NIC). client of having is The By called to iSCSI taking buy an initiator initiator the an expensive best technology communicates and an Fibre iSCSI from Channel storage with networking a HBA device storage and and is router switches, called DAS, or it a uses target. gateway, the SCSI which command knows how set to over map the the TCP/IP iSCSI commands protocol. to physical storage. As can be seen in figure 5.1, iSCSI uses existing network infrastructures. Instead of having to buy an expensive Fibre Channel HBA and ...

Context 2

... SAN protocol over TCP/IP is the so called Internet SCSI (iSCSI). As a NAS protocol we will discuss the NFS protocol in its latest release, which provides special enhancements for working better over existing internet infrastructures. In The We this conclude SAN chapter protocol this we chapter will over look TCP/IP by at further concrete is the comparing so distributed called these Internet storage protocols SCSI protocols (iSCSI). and evalu- which As are a ating NAS specified the protocol performance to work we will over of discuss NAS existing and the TCP/IP NFS SAN protocol based networks. protocols. in its latest release, which provides special enhancements for working better over existing internet infrastructures. We conclude this chapter by further comparing these protocols and evalu- ating the performance of NAS and SAN based protocols. Being a typical SAN protocol, it works on blocks (physical addressing). An iSCSI client is called an initiator and an iSCSI storage device is called a target. Instead of a HBA the iSCSI initiator uses an ordinary Network Interface Card (NIC). The iSCSI initiator communicates with a storage router or gateway, which knows how to map the iSCSI commands to physical storage. Internet Being Instead As can a be of typical SCSI a seen HBA (iSCSI) SAN in the figure 5.1, protocol, is iSCSI a SAN initiator iSCSI it technology works uses uses on existing blocks with an ordinary a (physical special network Network focus addressing). infrastructures. on Interface existing An infrastructure. iSCSI Card Instead (NIC). client of having is The By called to iSCSI taking buy an initiator initiator the an expensive best technology communicates and an Fibre iSCSI from Channel storage with networking a HBA device storage and and is router switches, called DAS, or it a uses target. gateway, the SCSI which command knows how set to over map the the TCP/IP iSCSI commands protocol. to physical storage. As can be seen in figure 5.1, iSCSI uses existing network infrastructures. Instead of having to buy an expensive Fibre Channel HBA and ...

Context 3

... can be seen in figure 5.1, iSCSI uses existing network infrastructures. ...

Context 4

... block-access protocol is the already introduced iSCSI protocol, and the file-access protocol is NFSv4. A very important performance related difference of the two approaches is that, although both protocols persist the metadata on the server, in the block-access protocol (see figure 5.2) the file system resides in the clients memory and only gets serialized to special blocks on the server. In file-access protocols (see figure 5.3) the meta-data resides entirely in the memory of the server -if the client wants to do meta data access, it has to issue network operations, for instance Remote Procedure Calls (RPC). ...

Context 5

... very important performance related difference of the two approaches is that, although both protocols persist the metadata on the server, in the block-access protocol (see figure 5.2) the file system resides in the clients memory and only gets serialized to special blocks on the server. In file-access protocols (see figure 5.3) the meta-data resides entirely in the memory of the server -if the client wants to do meta data access, it has to issue network operations, for instance Remote Procedure Calls (RPC). ...