ATTO Technology 2700C - Manual (Page 30)

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ATTO Technology Inc. iPBridge Installation and Operation Manual
An un-accelerated NIC does not offload anything
so the CPU must do much of the processing.
1 Verify that the adapter or NIC is sent to auto-
negotiate or forced to 1000 Mbs.
2 Set the MTU size to the largest MTU size
supported in the LAN/WAN using the Ethernet
page in the ATTO ExpressNAV interface.
9k frame size is the current optimized frame
size for the iPBridge. Many switch and router
vendors do not support the larger frame size of
9k or 16k.
3 Set the maximum transfer size to the most
efficient size for the intended target(s). For
many tape drives, 64k is the optimal setting.
Check applications
Some applications can be configured to change
transfer sizes. Configure the application for the
optimal size for the particular device(s) connected
to the iPBridge.
Check the host system
The faster the host, the faster your transfer times
will be. The work flow goes only as fast as the
slowest connection in the host system, so
transferring data from an IDE drive, 100Mb
connection, a DLT 4000, a high speed RAID
volume across the country, or other applications,
slows the system no matter how fast everything
else is in the system.
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 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
cycles on other operations, thus slowing down
performance.
Optimize ATTO ExpressNAV in Internet
Explorer
1 Go to the browser toolbar and select Tools
2 Select Internet Options
3 Select the Security tab
4 Select the Custom Level button.
5 On the menu presented, go to the Microsoft
VM, Java permissions and make sure
Disable Java is not selected.
6 Go to the Miscellaneous topic and select
METAREFRESH.
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:
FirstBurstLength
The maximum amount, in bytes, of unsolicited data an
iSCSI initiator may send to the target during the
execution of a single 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