第一部分
iscsi术语介绍
iscsi介绍
iscsi brings the idea of a block storage san to customers with no fibre channel infrastructure.iscsi is an ietf standard for encapsulating scsi control and data in tcp/ip packets,iscsi is encapsulated in tcp/ip and ethernet frames.tcp retransmission is used to handle dropped ethernet frames or significanttransmission errors.storage traffic can be intense relative to most lan traffic.this makes minimizing retransmits.minimizing dropped frames,and ensuring that you have'bet-the-business'ethernet infrastructure important when using iscsi.(ietf标准,通过以太网对iscsi进行封装的)
需要专门的fc交换机、fchba卡.至少千兆网络.
iscsi术语(1)iscsi initiaton
an iscsi initiator is a logical host-side device that serves the same function as a physical host bus adapter in fibre channel or scsi/sas.iscsi initiators can be software initiators,the other form of iscsi initiators are hardware initiators.an iscsi initiator is identified by an iscsi qualified name.an iscsi initiator uses an iscsi network portal that consists of one or more ip addresses.an iscsi initiator "logs in" to an iscsi target.(iscsi发起者就是esxi主机,有软件和硬件发起者,软件普通网卡,硬件hba卡,不管是发起者目标都会加入标识)
iscsi术语(2)iscsi target
an iscsi target is a logical target-side device that serves the same function as a target in fibre channel sans.it is the device that hosts iscsi luns and masks to specific iscsi initiators.an iscsi target is identified by an iscsi qualified name.an iscsi target uses an iscsi network portal that consists of one or more ip addresses.
iscsi术语(3)
iscsi logical unit(lun) an iscsi lun is a lun hosted by an iscsi target.there can be one or more luns "behind" a single iscsi target.
iscsi network portal an iscsi network portal is one or more ip addresses that are used by an iscsi initiator or iscsi target.(lun就是虚拟的盘)
iscsi术语(4)iqn
iscsi qualified name(iqn) an iscsi qualified name (iqn) serves the purpose of the wwn in fibre channel sans;it is the unique identifier for an iscsi initiator,target,or lun.the format of the iqn is based on the iscsi ietf standard.
iscsi术语(5)discovery
static/dynamic discovery iscsi uses a method of discovery where the iscsi initiator can query an iscsi target for the available luns.static discovery involves a manual configuration,whereas dynamic discovery issues an iscsi-standard sendtargets command to one of the iscsi targets on the array.this target then reports all the available targets and luns to that particular initiator.(动态发现lun盘)
