新版vSphere4的iscsi

之前在3.5,說實在的i-scsi的小毛病實在很多,這次的實驗計畫如下:

1.參數的改變效果

2.不同的target軟體影響會有多大

3.網卡真的會有神奇功能嗎

以下為官方文件對於參數檔案設置的說明

Header Digest

Increases data integrity. When header digest is enabled, the systemperforms a checksum over each iSCSI Protocol Data Unit’s (PDU’s)header part and verifies using the CRC32C algorithm.

Data Digest

Increases data integrity. When data digest is enabled, the systemperforms a checksum over each PDU's data part and verifies usingthe CRC32C algorithm.NOTE Systems that use Intel Nehalem processors offload the iSCSIdigest calculations for software iSCSI, thus reducing the impact onperformance.

MaximumOutstanding R2T

Defines the R2T (Ready to Transfer) PDUs that can be in transitionbefore an acknowledge PDU is received.

First Burst Length

Specifies the maximum amount of unsolicited data an iSCSI initiatorcan send to the target during the execution of a single SCSI command,in bytes.

Maximum BurstLength

Maximum SCSI data payload in a Data-In or a solicited Data-OutiSCSI sequence, in bytes.

Maximum ReceiveData Segment Length

Maximum data segment length, in bytes, that can be received in aniSCSI PDU.

Delayed ACK

Allows systems to delay acknowledgment of received data packets.