The IO operation at logical block address 0x0 for Disk 2 (PDO name: \Device\000000a3) was retried.

Hello Ravinder, I'm Henry, and I'd like to offer some insight into your issue. 

The warning message "The IO operation... was retried" (Event ID 153) means that a storage request from your server to the iSCSI storage array took too long to complete, so the system's disk driver had to send the request again.

Since you are using iSCSI, the issue is almost located in one of these three areas:

1. The Network Path: The most common cause. Congestion, packet loss, or misconfiguration on the network between your server and the storage.
2. The Storage Array (Target): The storage device itself is overloaded and cannot respond in time.
3. The Server (Initiator): A driver or configuration issue on your server is causing delays.

You can follow these troubleshooting steps below:

1. Check the Network Infrastructure:
   • Verify Dedicated Network: iSCSI traffic should be on its own dedicated, isolated network (using separate switches or VLANs) to avoid congestion from other network traffic.
   • Check for Packet Loss: Use tools to check for dropped packets on the switch ports connected to your server and storage array. A faulty cable, port, or switch is a common culprit.
   • Enable MPIO: Ensure Multipath I/O (MPIO) is correctly installed and configured on your server to provide load balancing and failover across multiple network paths to the storage.
2. Analyze Storage Array Performance:
   • Use your storage array's built-in monitoring tools to check its performance during the times the errors occur. Look for high disk latency, high CPU utilization on the storage processors, or other performance bottlenecks.
3. Update Server-Side Drivers and Firmware:
   • Ensure the firmware and drivers for your server's network adapters (NICs) are updated to the latest version recommended by the manufacturer. Outdated drivers are a frequent cause of performance issues.

Here are Data corruption and disk errors troubleshooting guidance Microsoft official document for your reference.

Hope one of these works for you. If you find this guidance helpful, you're welcome to click 'Accept Answer'—it helps others find useful solutions too.