MicroNet MaxNAS 2.5TB Server ReviewNemo - November 27, 2009
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RAID Data Protection
Multi-drive NAS devices provide an added layer of data protection by allowing you to set up RAID arrays that serve to protect against data loss in case of a hard drive failure. It should be noted that employing a RAID array is not a substitute for backing up your data. The MaxNAS offers support for several levels of RAID arrays that offer redundancy, including RAID 1/5/6/10 that provide redundancy either through mirroring (RAID 1/10) or striping with parity (RAID 5/6). The MaxNAS also features RAID 5 + hot spare capability, which allows you to designate a drive as a spare drive that can automatically be added to the array in the event of a drive failure.
In order to test the ability of the MaxNAS to automatically recover from a single drive failure, I configured the volume in different RAID types and then simulated a drive failure by removing one of the drives in the array from the system. Because the MaxNAS supports hot-swapping, drives can be removed and replaced without powering the unit down. Removing a drive will cause the System Error LED on the front of the unit to show red; had a drive actually failed, instead of being removed, the Drive Fault LED would have blinked red to indicate which drive was at fault. Pulling a drive also results in an e-mail being sent by the MaxNAS alerting you of the problem.
The first test I did was with a RAID 5 array using all five drives. I 'failed' drive 5 by removing the tray from the system and checked the RAID Information page, which showed the array status as Degraded and the Disks Used column showed disk 5 was missing. I replaced the 'failed' drive by reinstalling the tray in the enclosure. In a real life scenario you would have physically replace the drive with a new one, but since I only have five drives for testing, I was forced to reinsert the old drive back in the system. On the RAID Configuration screen I clicked on the Spare checkbox for Disk 5 and then clicked on the Add Spare button. Because I was reusing an existing drive from the array, the MaxNAS popped up a warning dialog and after clicking the OK button, the RAID Information page shows the system has automatically begun rebuilding the RAID 5 array, a process that will take over 7.5 hours. During the rebuild process, the volume is still accessible with all files intact and no data was lost.
I repeated the test by 'failing' a drive in a 4-drive RAID 5 with a hot spare and saw the system automatically begin rebuilding the array using the spare drive with no user intervention. The same was true when I tested a RAID 1 array and RAID 10 array that both had a hot spare drive allocated. The MaxNAS performed its array recovery process flawlessly and sent e-mail notifications alerting of the failure, the start of the rebuild process and again when the array rebuild was complete.
If you read the performance test results, you noticed we showed results for iSCSI under each volume configuration and you may be wondering just what it is and how it’s used. Internet Small Computer Systems Interface (iSCSI) is an Internet, or IP-based, protocol used in storage networks to exchange SCSI commands over the network. This allows you to consolidate storage in arrays such as the MaxNAS, while having the storage appear to the client as a local drive. Additionally, iSCSI lets you take advantage of existing IP network infrastructure without having to install expensive interconnections like Fibre Channel. As we saw in the configuration section of the review, the MaxNAS can function as an iSCSI target, but the client computer must have an iSCSI initiator, either a piece of hardware such as a host bus adapter card or a software initiator. We’ll be using Microsoft’s iSCSI initiator. Since we tested using Windows XP, I had to download the Microsoft iSCSI Software Initiator Version 2.08 from Microsoft's web site. The iSCSI initiator is included in Vista and Windows Server 2008 and later operating systems.
We already covered setting up an iSCSI target in the configuration section of the review, so let's take a look at setting up the initiator software and mapping a link to the iSCSI target. Launching the iSCSI initiator software brings up a dialog with several tabs. Clicking on the Discovery tab will allow you to add a target portal, which you do by clicking the Add button and keying in the IP address of the MaxNAS unit.
Once the target has been identified, you can use the Targets tab to log on to the target using the Log On button.
After you have chosen the proper target and clicked the OK button, you should be able to see a new disk show up under Computer Management>Disk Management in Windows. From this point you can initialize the disk and create a partition and Windows will treat the space on the MaxNAS iSCSI target just as if it were a direct attached disk on your computer.
I found setting up the target on the MaxNAS to be be very straightforward and setting up the initiator software to be quick and painless. Being able to use a storage pool for applications such as a database or an Exchange server gives you a lot of flexibility and doesn't lock you into a fixed amount of storage. I would like to point out that using an iSCSI target is meant to be used by a single application and is not for shared folders; for that you need to stick to using the shares on the NAS.