iSCSI Speed - Why so inconsistant?
Posted on 2013-11-27
I have created tow SANs using OPEN-E for an Active -Active High Availablility Failover. I also Have created a Microsoft 2008 Cluster R2. I have two iscsi ports in each 2008 Server Node.
On Node A - I was able to grab a 7GB file and copy and paste it to my desktop in 12 seconds. It showed 500+ MBs a second.
However on Node B - I am only able to get 120 MBs a second and it takes 45 seconds to copy the same file. The two nodes are the exact same spec, processor, memory, etc...
Nic settings are the same. I used dells recomendation to set up iSCSI network accept for Jumbo frames and the Netsh commands.
I double checked the cards i didn't miss anything. The switches that are used in the high availability setup are the same.
I stopped and restarted the cluster and now Node one no longer copies at 500mbs a second. Now it only copies at 120mbs and takes 45 seconds to copy the same file.
What's weird is when it was copying at 500mbs a second I couln't see any iSCSI traffic on the TASK MANAGER NEtwork monitor tab and it said 0% under iSCSI Nics during the lightning fast copy . Now I can see the graph during the slower copy and it shows about 55%.
Can this be explained. I am using MPIO.