Check The Operating System; Use The Atto Iscsi Performance Configuration Tool For Windows - ATTO Technology iPBridge 2600 Installation And Operation Manual

1 Verify that the iSCSI storage adapter or NIC is
connected to the fastest PCI bus connector
supported by the adapter or NIC.
If the adapter supports PCI-X, place the
adapter in a PCI-X slot. If one is not available,
the host might not achieve the optimal
performance capable from the adapter.
Even placing a PCI-X adapter into a 64 bit 66
MHz slot loses performance. Some adapters
adjust clock speed depending on the speed of
the PCI slot into which they are plugged.
2 The host OS disk and swap disk/partition/file
should be on a high speed drive such as a SCSI
drive to minimize the time needed to access the
host's virtual memory.
The more memory a system has, the less time
it spends accessing virtual memory (hard drive
space).

Check the Operating System

If possible, eliminate swap space and virtual drives
which require large amounts of system memory.
However, the OS might not allow the elimination of
swap space. An OS set to run many kinds of different
servers spends much of its CPU cycle on other
operations, thus slowing down performance.
Use the ATTO iSCSI performance
configuration tool for Windows
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:
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ATTO Technology Inc. iPBridge Installation and Operation Manual
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
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