How to Speed Up Your NAS With iSCSI

Hit the Target

With the iSCSI target created, you must now connect to it through the iSCSI initiator on the client Windows PC. To do so, click Start, type iSCSI into the Search/Run field, and press Enter (or go to Start > Control Panel > System and Security > Administrative Tools > iSCSI Initiator). If you see a message indicating that the iSCSI service is not running, go ahead and allow it, and the iSCSI initiator will open.

Select the Discovery tab, and then click the Discover Portal button. In the window that opens, enter the IP address of your NAS device or server hosting the iSCSI target (ours was 192.168.1.100) in the necessary field. Leave the port setting alone, assuming that you didn’t specify a custom iSCSI port earlier; by default, iSCSI will use port 3260. Note that if you enabled CHAP authentication earlier, you should click the Advanced button here and enter the CHAP login credentials in the necessary fields. Otherwise, just click OK, and the IP address of your NAS or server should appear in the list of Target portals.

If the target is not found and listed, confirm that you entered the IP address correctly and that the necessary port is open in any firewall application you may be running.

Open the iSCSI Initiator utility in Windows to tell your PC where to find your NAS drive.

Once the server is in the list of Target portals, click the Targets tab at the top. The iSCSI target you created earlier should show up in the groups of discovered targets in the middle of the window. Click the target to highlight it, and then click the Connect button. In the Connect To Target dialog box that opens, check Add this connection to the list of Favorite Targets... and click OK. Then click OK in the iSCSI Initiator Properties window to close it.

If everything is properly configured, you should see your NAS drive appear in the iSCSI Initiator list of targets.

Now that the client system is connected to the iSCSI target, you must format the target. To do so, follow the same procedure that you would for any local drive. Click the Start button, and then right-click Computer and select Manage from the menu. In the Computer Management utility that opens, click Disk Management in the Storage subsection in the left pane. You should immediately see an Initialize Disk dialog box. Ensure that the disk is checked in the 'Select disks' field, and then choose your preferred partition type (we used MBR) and click OK. Follow the on-screen prompts to specify the volume size, assign a drive letter, and choose a file system and volume label. Click Finish. Once the formatting is complete, a new drive letter should be available and ready to use. You can now transfer files and run programs from your NAS drive (no matter where it may be) as though it were just another drive in your PC.

Once your PC sees your NAS drive as an iSCSI target, you can format it just as you would any other hard drive.

Performance Comparison

To quantify the performance benefits of using a remote NAS drive connected via iSCSI, we ran a couple of disk benchmarks on our setup. Since we had dedicated half of the available storage space on our NAS to the iSCSI target and the other half to an EXT4 network share, we were able to have the iSCSI initiator connected and a drive letter mapped to the NAS to test speeds when accessing the NAS via iSCSI versus a standard mapped network drive. Here are our results.

As you can see above, the ATTO Disk Benchmark didn't show much of a performance difference between the mapped network drive and iSCSI, although the mapped drive appeared to offer slightly more bandwidth overall. However, this is a relatively light-duty benchmark that tests only sequential transfers.

The CrystalDiskMark benchmark tests both sequential and random transfers using a couple of different file sizes. In this benchmark, the iSCSI target performed significantly better overall. Write speeds were similar between iSCSI and the standard mapped network drive, but read speeds were roughly 30 to 40 percent better with iSCSI. As these results show, the ability to access or format your NAS as a local drive and run programs from it isn't the only benefit you can derive from iSCSI--the technology also allows your system to read data from the drive faster than it could otherwise. If you work with NAS drives at home or at the office, iSCSI offers an excellent (and free) way to boost performance.

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