StorTrends MPIO MCS Comparison
MPIO/MCS Comparison
There are two main technologies using Microsoft’s iSCSI initiator that allows I/O to travel through redundant paths with iSCSI. The two technologies are Multipath I/O (MPIO) and Multiple Connections per Session (MCS). MPIO allows the initiator to login multiple sessions to the same target and aggregate the duplicate devices into a single devices exposed to Windows. The CPU efficiency of MPIO comes with a major disadvantage in that MPIO is not currently supported for VSS-aware snapshots with SnapTrends (StorTrends iTX’s HAK). MCS is a simpler version in that it doesn’t utilize an additional utility for configuration. MCS maximizes throughput while ensuring the availability of iSCSI I/O through multiple networks. Microsoft does allow both features to be configured together, although it raises complexities reducing the overall I/O performance. StorTrends customers should choose their path wisely (no pun intended) depending on their specific I/O expectations.
Configuring iTX
NOTE: If you have StorTrends 2.8 software (iTX 3400i/3500i), this is already configured to the optimal setting of 4 connections.
Step 1: Login to ManageTrends using any of the accessible IP’s of the StorTrends appliance.
Step 2: Select the Control Panel icon within the left pane of ManageTrends.
Step 3: Click on the Portal Settings icon within the iSCSI section of ManageTrends Control Panel.
Step 4: Click on the Advanced Settings link at the top right of the iSCSI – Portal Settings page.
Step 5: If configuring MCS, select the drop-down menu to the right of the Maximum Connections and pick the number that best suits your configuration. By default, the optimum configuration is 4 connections.
Step 6: If configuring MPIO, Be sure that the Portal Tag for each Alias is in an incrementing fashion and that each portal is enabled. If the Portal Tags are all the same, you will need to disable each port, then change the Portal Tag, and finally re-enable the port.
Configuring Microsoft MCS
Step 1: Login to ManageTrends using any of the accessible IP’s of the StorTrends appliance.
Step 2: Select the iSCSI Initiator from the Tools menu in Server Manager.
Step 3: Click on the Discovery tab and insert the StorTrends IP that you intend to run iSCSI traffic through.
NOTE: The portal must be enabled on this IP within the StorTrends appliance. See Step 4 above.
Step 4: Click on the Targets tab, select the name of the LUN that you would like to connect to, then select the connect button.
Step 5: Click on the Advanced… button to select the specific IP that you would like iSCSI traffic to go through.
Step 6: Within the Advanced Settings page, select the MS iSCSI Initiator as the Local adapter and then the Initiator IP and StorTrends IP that you plan on running the iSCSI traffic through.
Step 7: Now, within the iSCSI Initiator Properties page, make sure that this same LUN is selected and then select the Properties… button towards the bottom. Step 8: Select the MCS… button at the bottom of the session Properties page. Step 9: Here you can see the current connection that is configured from the initiator to the StorTrends appliance. To add a connection, just simply click on the Add… button below the connection list. Step 10: Just like before, select the Advanced… button to specifically select the iSCSI traffic IPs. Step 11: Select the Initiator IP and the StorTrends IP that you intend on using for iSCSI traffic and then select the OK button at the bottom of the Advanced Settings box. Step 12: After clicking OK to accept the settings for the new connection, you can see the additional connection that was configured within the connection list of the MCS page. Repeat the 10 steps above process 2 more times for up to 8 maximum connections (if that is what you selected to be the maximum number of connections per session).
Configuring Microsoft MPIO
Multipath I/O (MPIO) is not a default feature in Windows Server. Therefore, the following steps will guide you through installing and configuring the MPIO feature. Step 1: Open Server Manager. To open Server Manager, hover your mouse over the bottom left corner of the screen until the ‘Start’ icon appears and click it. From the start menu, click Server Manager. Step 2: In Server Manager, click on ‘Manage’ and then ‘Add Roles and Features’. Step 3: The Add Roles and Features Wizard will pop up. On the ‘Before you begin’ page, click ‘Next’. On the ‘Select installation type’ page, choose ‘Role-based or feature-based installation’ and click ‘Next’. Step 4: On the ‘Select destination server’ page, select ‘Select a server from the server pool’ and be sure to select the server you wish to install MPIO on. Click ‘Next’. Step 5: MPIO is a feature, so on the ‘Select server roles’ page, simply click ‘Next’. On the ‘Select features’ page, scroll down in the ‘Features’ box until you find ‘Multipath I/O’ and select the checkbox next to it. Click ‘Next’. Step 6: On the ‘Confirm installation selections’ page, click ‘Install’. Step 7: When installation has completed, on the ‘Installation progress’ page, click ‘Close’. Step 8: Next, open the MPIO control panel. To open the MPIO control panel, go back to the Server Manager and click on ‘Tools’, followed by ‘MPIO’ Step 9: Click ‘Add’ and enter the following “AMI StorTrends iTX ” (there should be five (5) spaces between ‘AMI’ and ‘StorTrends’ and then two (2) more spaces after ‘iTX’ in order to meet the requirements for a Vendor ID of eight (8) and a Product ID of sixteen(16)). Click ‘OK’ on both windows. When prompted to restart the computer, click ‘Yes’.click MPIO Step 10: Select the iSCSI initiator by going to the Server Manager and clicking on ‘Tools’ followed by ‘iSCSI Initiator’. Step 11: Click on the Discovery tab and then click on ‘Discover Portal…’ and insert the first StorTrends IP that you intend to run iSCSI traffic through. NOTE: The portal must be enabled on this IP within the StorTrends appliance. Seen from Step 4 above (in “Configuring iTX”). Step 12: On the ‘Discover Target Portal’ window, be sure to click on the ‘Advanced…’ button and on the ‘Advanced Settings’ window, be sure to select ‘Microsoft iSCSI Initiator’ for ‘Local adapter’ and choose the IP that matches the subnet of the StorTrends IP you entered in ‘Initiator IP’. Click ‘OK’ until you are back at the ‘iSCSI Initiator Properties’ window. Step 13: Click on the Targets tab and choose the target that correlates to the volume you are trying to connect to, then click on ‘Connect’. Step 14: On the ‘Connect to Target’ window, be sure to check both options and then click on ‘Advanced…’. Step 15: In the ‘Advanced Settings’ window, be sure to select ‘Microsoft iSCSI Initiator’ for ‘Local adapter’ and then choose the corresponding IPs for both the initiator and the target portal within the same subnet. Click ‘OK’ until you are back at the ‘iSCSI Initiator Properties’ window. Step 16: Click on the Discovery tab and choose the portal that you added previously, then click on ‘Remove’ and click ‘OK’ when the ‘Remove Target Portal’ window pops up. Step 17: Repeat steps 11 through 15 for the other StorTrends IPs that you intend to run iSCSI traffic through.