The 'Safe Server Module' (SSM) from Tranquil PC offers the Windows Home Server enthusiast one solution for protecting their operating system and primary data partition from potential HDD failure. It comes delivered with 2x 500GB 2.5” Samsung HDDs, prepared in a RAID 1 mirror, including a Tranquil build of Windows Home Server (PP3), Silicon Image's software for configuring and managing the SSM, Sata cable and mounting screws and as a bonus, - AVA Media CD Ripping software. For this review I'll focus just on the SSM - and more specifically, my test results with a HP MediaSmart EX495 and an ACER H341. In Part 2 I'll review Silicon Image's software.
First off, I did have some expectations that the packaging that I would receive the SSM in would be comparable to other online purchases I've made but it wasn't. Of course, when one gets something like this wrapped simply in a little bit of bubble plastic and thrown in a box for shipping - I for one always get immediately concerned that it may have been damaged in shipping. It wasn't.
The other thing I immediately noticed was that there was two holes drilled - what appears to be by hand. These additional holes are to accommodate tool-less drive trays like the HP/Acer WHS models. This is surely an after thought to the superb construction of the SSM. No problem, but I will mention that one of the holes wasn't deep enough and my Dremel had to remedy that.
With both OEM's there was no issue fitting the SSM into either drive caddy. With the SSM being front loading one must remove the module to access the drives, but since this would only be done in the event of a drive failure this shouldn’t pose any inconvenience. The unit itself is constructed of a solid piece of aluminum machined to a nice finish. The only plastic bits are the front and rear – these too appear very solid.
As mentioned, the SSM comes pre-loaded with two 500GB 2.5” Samsung HDDs already prepared in a RAID 1 mirror. This, I believe, is the maximum capacity the SSM supports.
To access either drive one simply slides the ‘safety’ lock and opens the drive bay door. This has the effect of safely un-seating the drive for removal. Installing a drive is much the same – slide a drive partially in and close the door. The hinge on each drive bay door is designed in such a manner to push the remainder of the drive in - seating it safely in place. Setting the ‘safety’ lock prevents accidental opening whether one is transporting the unit or its installed in a home build where it might be more exposed than in the HP or ACER models.
On the front there is also three indicator LEDs offering ‘at-a-glance’ status. These LEDs will indicate along with drive activity, drive failure and when the mirror is being rebuilt. On the back, is the SATA/Power connectors along with a USB 2.0 port and dip switches for setting the various modes. Although one can re-configure the device for other modes I didn’t test that particular functionality other than RAID 1. Setting the dip switches as shown and pressing the ‘change mode’ button immediately starts the device configuring and setting up the chosen array – this can be done with the unit simply being connected to a power source. No need to install the unit. Alternatively, this can be done via software.
To incorporate the SSM into your WHS the recommended option is to do a server recovery. For me, this was the perfect opportunity to try cloning the existing system disk following these instructions and a pair of these USB to Sata adapters. Success!
Either way, one now has the old system disk that they can re-install into their existing pool of drives.
For testing purposes I was curious how the performance of the SSM would compare to
the OEM drives. Even though my reason for purchasing was to add the redundancy offered by mirroring my system drive - knowing what I could expect (relatively) under various conditions was important. That said, readers should review these results in that light.
Testing consisted of measuring various performance parameters under normal operation, during a single drive failure and through the rebuilding process. For these tests I used IoMeter and although I conducted tests using both servers the results were consistent in that the Acer H341 was generally less responsive than the EX495 - due largely in part to it's processor and not the SSM. Also, no other drives were present in the pool besides just the system drive.
Response times improved significantly once the array was up and running. As one can see even with a drive failure response times didn't take much of hit. It was only during the rebuild process that response time almost doubled but this is understandable.
Under each condition there was no noticeable operational difference - even during a single drive failure WHS will still report the SSM as healthy. This is why it's important to utilize the included monitoring software so that one is notified. Optionally, one could check the LED's on the front of the SSM but they're rather difficult to see once the SSM is placed inside the OEM's drive caddy. I also checked the status with a couple of disk management add-ins and they didn't show anything different
After a couple of weeks of hammering the unit in my test box I incorporated it into our office production server. That was almost 3 weeks ago and there haven't been any issues. I wouldn't hesitate recommending the SSM to anyone even though there may be less expensive options out there by now.
a guest post by SLicK
A post in the HSS forums is here for questions and comments for SLicK.