MicroNet MaxNAS 2.5TB Server ReviewNemo - November 27, 2009
» Discuss this article (3)
Expand RAID Space
In the previous example we built the array and allocated 25% of the available space to data storage. If your future storage requirements end up requiring more space you can go the RAID Configuration screen and use the Expand button to allocate additional space. The Expand RAID Space page shows 75% of the space on the volume as unallocated and you can specify some or all of that to be allocated to data storage. I specified 30% thinking it would add an additional 5% to the amount already allocated, but instead its additive so I ended up with a total of 55% of the disk space being allocated. There is no provision to reduce the allocation once you finalize the process which again requires a double confirmation by clicking OK to confirm then typing 'Yes' in the pop-up window just like we deleted an existing array.
Volume expansion is a very useful feature and provides a lot of flexibility. One example that comes to mind is if you one day need more space that five 500GB drives can offer, you could increase your storage capacity by replacing all the disks with larger drives one at a time letting the array rebuild after installing each drive. Once all the drives have been upgraded you could use the Expand RAID Space function to access the newly available space.
The MaxNAS also offers the ability to migrate an existing RAID array to a more comprehensive level such as moving from RAID 1 to RAID 0 or RAID 0/RAID 1 to RAID 5. In addition you can use the migrate feature to append an unused drive to an existing RAID 0 or RAID 5 array.
We started this example with a 3-drive RAID 5 array and intentionally left one drive (disk 4) unused. We can go into the RAID Configuration page and choose Migrate RAID to append the unused volume to the array. The RAID 5 -> RAID 5 radio button is the only option available so clicking it allows you to choose Disk 4 by clicking the Available Disk checkbox. Again, you must go through the two-level confirmation process to make sure this is what you intend to do. You'll receive a system notification that the RAID setting were successful and the rebuild process begins. Even though you are only adding a single drive, the process is similar to building a new array from scratch and will take several hours during which the RAID volume will be unavailable.
The final option on the RAID Configuration page is the Space Allocation button which enables you to reserve space for USB and iSCSI targets.
The MaxNAS has a USB Target Mode Port on the rear panel that enables it to be connected directly to a client PC with the included cable and be used as an external USB drive. In order for this to work you need to allocate space on the RAID volume to store the data. Clicking on the Space Allocation button bring up a second RAID Information page where you can use the Target USB button to allocate any free space to be used for the target USB drive. You can choose a percentage value of the remaining free space to be used for the USB drive. Once you click OK and confirm the create process you'll receive a system notification that the space was successfully allocated.
Internet SCSI (iSCSI) is a storage networking protocol that allows block level I/O across IP networks. It can be used to set up a storage area network (SAN) using existing Ethernet infrastructure and allows clients called 'initiators' to send SCSI commands to SCSI targets on the network. It is not a file-sharing protocol like SMB/CIFS and is intended to connect a single client to the storage device. With the proper initiator (either hardware of software) configured on the client, the storage volume on the MaxNAS will appear as a local drive on the client side.
Just like allocating space for the target USB, you can also allocate space for an iSCSI target off the RAID Information page using the iSCSI Target button. As before, you can choose a percentage of the available space to allocate to the iSCSI target and click the Enable radio button to make the target visible. Other options include setting up the iSCSI qualified name (IQN) consisting of the target name, IQN year and month as well as enable the challenge-handshake authentication protocol (CHAP) if desired. Clicking the OK button and responding to the confirmation dialog will result in a system confirmation message telling you the target was successfully created. You can create multiple iSCSI targets and use the Modify button to change any target information.
Now that we've created the initial array and set up space for the data and USB and iSCSI targets the RAID Information page shows a nice snapshot of our handiwork.
There are a few more options in the Storage section we need to check out.