Thecus N3200XXX NAS Server ReviewNemo - October 6, 2011
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The storage section is used to monitor disk information and health, create disk volumes, mount ISO images, and manage share folders on the volume.
The Disk Information section provides basic information on all the disks installed in the N3200XXX. Information on each disk includes formatted capacity, model number, firmware version, health status, and an option to scan the physical disk for bad sectors. The total combined capacity is also displayed. Another feature available is Disk Power Management, which allows you to set an idle time from 30 minutes to two hours, in 30-minute increments, after which the NAS will power down the drives.
Double-clicking on the Status column entry for each drive will display the S.M.A.R.T. information dialog for that particular drive, including disk model number, power on hours, temperature, and other disk information. You also have the option of selecting the short or long SMART test, which you can launch using the Test button.
The RAID Management screen serves a couple of functions. It is where you can create a new volume on the system, either as a single volume or one of the supported RAID levels. It is also where you can monitor the status of the volume, get information on available space, or remove an existing volume.
With a new setup, there is no existing volume as evidenced by the lack of any volume information on the RAID Management page. We need to create a new volume, which begins with clicking on the Create icon in the upper left corner of the RAID Management pane. Once you click on the Create icon, the system will walk you through the process step by step using a series of RAID Volume Creation screens. This is a six-step process and you can go back and forth between screens until the final creation step. If you haven't decided on the volume type, now would be a good idea to determine which volume type you are going to choose. The N3200XXX supports up to three disks, so you have four different choices: JBOD, or Just a Bunch of Disks, (multiple drives are configured as a single large volume and is not technically RAID), RAID 0 (also known as striping, where two or more identical drives are set up as one larger drive), RAID 1 (also known as mirroring, where one drive maintains a copy of the other drive), and RAID 5 (uses striping similar to RAID 0, but also provides redundancy for data protection) The benefits and limitations of each type of setup are outside the scope of our review, but a concise explanation can be found in The Official OCC RAID Guide, Version 2.0.
Your decision on RAID volume type will likely force your hand when determining the number of disks to use, which is the first step. We're going to create a RAID 5 volume for our example, so we need to choose all three drives, the minimum required for a RAID 5 volume. To select the disk, we need to check each box in the Used column. You'll notice there is also a 'Spare' column, which could be used to designate a hot spare for a RAID 5, if the NAS supported more than three drives. The next step is to determine the RAID level as mentioned above. The third step is to fill in the RAID Property Setup information. You can name the RAID volume — useful if you were forming multiple RAID volumes on a single server — as well as designate whether this is to be the Master RAID, as one RAID volume must be the Master in a multiple-RAID setup. The N3200XXX also supports volume encryption, which must be selected at the time the volume is created. A USB drive plugged into one of the rear USB ports is required to store the encrypted password. The Quick RAID option speeds up the volume creation process for those setups that do not have an existing partition.
The fourth step in the process is the RAID System Setup, which involves selecting a stripe size, choosing the file system, and determining how much of the available space to use. Stripe size refers to the size of the blocks of data that are written across the disks in the RAID volume. There is no magic formula that will guarantee the exact right stripe size, as performance will change based on the size of the files your are writing to and reading from the RAID volume. As a general rule of thumb, if you are mostly dealing with larger files, your performance will improve with a larger stripe size. The N3200XXX supports stripe sizes from 32-4096KB. We will be using the default size of 64KB. The OS used by the N3200XXX is Linux-based and you have a choice of four different file systems ranging from the venerable EXT3 to the more recent EXT4, with ZFS and XFS also supported. Like choosing the stripe size, there is no perfect answer for all situations. We are going with the default EXT4 file system and we'll leave it up to you to research the right choice for your situation. The last choice to make in this step is how much, percentage-wise, of the available space to allocate to the volume. By not allocating all the available space now, you retain the flexibility of using some of the space as an iSCSI target (more on this in the next section) while still having the option of allocating more space to the volume in the future. You set the desired percentage using the slider on the screen. For this example, we set it to 50% and clicked the Next button. Finally we get a chance to review and confirm our choices prior to creating the RAID volume: we are using three disks to create a RAID 5 volume with a stripe size of 64KB, using the EXT4 file system, while allocating 50% of the available space.
The system warns you that all active services will be stopped while the RAID volume is created and then processes for a minute or two prior to asking you to press the Finish button to kick off the RAID volume creation. The actual process of formatting and initializing the RAID volume can take several hours depending on the number and size of the disks used, as well as the space allocated to the volume. This is not a 'go get a cup of coffee' moment, it's more of a 'kick it off and go to bed' moment while the process runs overnight.
Now that you've had a refreshing night's sleep, and if all went well, you should be able to wake up to a page that looks like the screen shot below, with the new RAID volume showing a healthy status and a pie chart depicting how much space was allocated to the volume and home much remains unused.
Internet SCSI, or iSCSI, is a networking protocol that allows block level access over IP networks. In the Space Allocation section, you can create an iSCSI target on the N3200XXX and then access the storage from a client computer running an iSCSI initiator, either hardware-based or through a software client. You can then permanently assign a drive to the storage on the NAS and have it appear as a local drive.
To add an iSCSI target, just click on the Add button below the iSCSI Target tab, which brings up the iSCSI Volume dialog. The first order of business is to determine how much available space you want to allocate to the volume. In our example, we can allocate up to 50%, which really means 50% of the disk space is unallocated (not used) and is available to be used by the iSCSI volume. Again we use the slider tool to set the amount of space to around half of the unallocated space. You can enable or disable the iSCSI volume using the radio buttons here. If you leave it to the default value of disabled, you won't be able to access it as the initiator will not be able to see it. The target name can consist of numeric values 0-9 and lowercase alpha characters a-z only. The iqn_Year, iqn_Month, and LUN ID all combine with the target name to create a unique target identifier (in this example it works out to "iqn.2011-8.com.thecus:raid.iscsi0.vg0.n3200xxx"). You can specify whether to use challenge-handshake authentication protocol (CHAP) by clicking the CHAP radio button and supplying the user name and password.
Once you press the OK button, the system will ask you to confirm the iSCSI target volume creation and then notify you when it is completed. The newly created volume appears in the Volume Allocation List pane and you can also see the space allocated to the volume reflected in the pie chart in the RAID Management section. You can create up to five iSCSI target volumes on the N3200XXX.
With the iSCSI target volume in place, you also have access to the Modify, Expand, and Delete buttons. The Modify button lets you modify any of the information entered when the iSCSI volume was created. The Expand option adds flexibility to your management options, as you can add capacity to the volume as needed instead of overallocating space at the start. You use the now-familiar slider to add capacity from the pool of unallocated space on the NAS. The next step is to hit the Expand button and respond with a typed 'Yes' that you wish to expand. As with any changes on the NAS involving the disks, it is always prudent to back up your data first. The systems pops up a dialog when the expansion process is complete and you can see the newly added space reflected in the Volume Allocation List for that volume. You can highlight a volume in the list and press the Delete button to permanently remove it from the NAS. You will see a warning dialog informing you the data will be removed as well.
A new feature I've not seen before is the ability to add iSCSI Thin-Provision Targets. Thin-provisioning is a concept found in more sophisticated storage area networks and may not be that useful in a SOHO environment. Traditional methods, such as those we have seen above, are called 'fat provisioning', as you allocate dedicated physical storage to a volume whether or not that storage is actually being used. That space, once allocated, can't be used for anything else until it is freed up and re-allocated. This can lead to buying more physical disk space than you actually need. With thin-provisioning, you can over-allocate space so that the system can view more space than is physically there. Thin-provisioning means each target only uses the space it needs, driving utilization rates close to 100%. This also means you can more easily add space and expand volumes as you don't have to rebuild the file system if it already thinks there is more space due to over allocation.
In the Thecus implementation of this feature, you create a single iSCSI thin-provision volume and then create up to five thin-provision targets on that volume. The N3200XXX will issue a notification when 90% of the physical iSCSI Thin-Provision volume has been used, allowing you time to add additional space. Creating the volume is identical to a regular target, where you click the Add button and use the slider to determine the amount of space to allocate to the volume.
With the iSCSI thin-provision volume created, we can then create up to five iSCSI targets. Just as we did with a regular iSCSI target above, we begin by clicking the Add button and selecting the virtual size. Even though there is currently only a bit over 550GB of physical disk space, I can create a target of up to 16TB in size. I'll choose a size that is a bit more reasonable, like something close to 1TB. Once all the appropriate information is entered, you can click OK to create the target after confirming that it is okay to do so. The final tab is labeled Advance Options (sic) and here you can set the block size of either 512 byte or 4K bytes. You can also choose whether to used a CRC/checksum. If you enable them here on the NAS, be sure to enable them on the initiator side as well.
That takes us through three of the six sections in the Storage category. Let's take a quick break and pick up again on the next page with a look at the remainder of the items starting with something called NAS Stacking.