Enhance Performance; Iscsi Performance Configuration Tool (Windows Only) - ATTO Technology iPBridge 1550D Installation And Operation Manual

Enhance performance

Note
If you used ExpressWizard to set up your
iPBridge, changing these parameters may
interfere with ExpressWizard settings.
Default values, even if you have not used the
ExpressWizard, are appropriate for most
configurations, but may be modified.
1 Follow the Preliminary
2 On the iSCSI page, enable SpeedWrite.
3 On the Ethernet page, change MTU to 9014.
Note
If you change the MTU on the iPBridge, you
must enable jumbo frames on your initiator
and change the MTU on the initiator.
4 For Windows operating systems, use the ATTO
iSCSI performance configuration tool
(Windows only).
iSCSI performance configuration tool
(Windows only)
The ATTO iSCSI performance configuration tool
changes the Windows registry parameters for
Microsoft iSCSI Initiator and TCP/IP to enhance
overall data throughput.
1 From the CD which came with your iPBridge,
copy the Perftune.exe file to your hard drive.
2 Execute the program.
3 Click on Use ATTO Performance Settings.
Settings take effect on the next system reboot.
The following settings are affected:
FirstBurstLength
The maximum amount, in bytes, of unsolicited data an
iSCSI initiator may send to the target during the
execution of a single SCSI command including the
immediate data and the sequence of unsolicited Data-Out
PDUs which follow the command. FirstBurstLength
cannot exceed MaxBurstLength
ATTO value: 1048576 decimal 00100000 hex
steps.
MaxBurstLength
The maximum SCSI data payload, in bytes, in a Data-In
or a solicited Data-Out iSCSI sequence. A sequence
consists of one or more consecutive Data-In or Data-Out
PDUs that end with a Data-In or Data-Out PDU with the
F bit set to one.
ATTO value: 1048576 decimal 00100000 hex
MaxRecvDataSegmentLength
The maximum data segment length, in bytes, that a
transmitter (initiator or target) can receive in an iSCSI
PDU. The transmitter is required to send PDUs with a
data segment that does not exceed
MaxRecvDataSegmentLength of the receiver.
ATTO value: 1048576 decimal 00100000 hex
MaxTransferLength
The maximum number of bytes that may be transferred by
a single SCSI request block (SRB).
ATTO value 1048576 decimal 00100000 hex
SrbTimeoutDelta
The maximum amount of time, in seconds, before an SRB
request will time out.
ATTO value 300 decimal 0000012c hex
Tcp1323Opts
This parameter controls RFC 1323 time stamps and
window-scaling options. Time stamps and window
scaling are enabled by default, but can be manipulated
with flag bits. Bit 0 controls window scaling and bit 1
controls time stamps.
ATTO value: 1
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