Device overview -Out Of The Box
The topic of the day is “SAN Storage Out Of The Box”, so we will see which items a SAN can offer us as at a first visual impact.
For this demo serie, we will use the smallest unit of the Oceanstor product line: S2200T.
The S2200T is the smallest one as hardware solution, but it has standard SAN capabilities and, more important, it uses the same management console as the bigger ones: the ISM (integrated Storage Management)
Let’s start analyze what we have under the front cover.
This model holds 12 hard disks, sized 3,5”.
Another version exists holding 24 2” sized disks.
The top first 4 HDDs are labelled differently (yellow stickers) as they have a double function: simple storage and COFFER.
A COFFER disk is used to temporarily store the raw data before they are actually written on the RAID: so this is both a speed-up solution and a safety feature in the event of a blackout. The COFFER function reserves a small portion of the disk (in our case about 20 GB) to perform its task, then these 4 discs will be with slightly reduced a capacity compared to the others.
Very important, we have also the overall status indicators near the left border:
Alarm indicator is triangular in shape and flashes red in the same way for both simple warnings and important alerts.
Power indicator is circular and has three states:
-Off : the storage is powered off.
-Blinking Green: startup procedure or shutdown procedure in progress –Unit unavailable.
-Solid Green: storage ok and fully available.
Now, let’s check the rear side.
We can immediately notice that all components are redunded.
Looking from border to middle, we have power supplies, fans and controllers.
Fans also include BBUs (battery backup units)
BBUs work coupled with COFFER disks, as we told before.
In the middle area, we have the controllers: controller A is the upper one, and controller B is the lower one.
Both of them provide an expansion slot: it can be populated, for example, by a Fiber Channel card.
Controllers also supply the mini-sas port, used to connect the external disk enclosures
The controllers are the real heart of the storage: they permit redundant communications between the disks and the application servers.
So, here in the rear side, we have a lot of connectors; in the sample picture we see both ethernet connectors and FC (Fiber Channel) connectors.
The group of four RJ-45 ports on the right are ethernet ones for i-SCSI protocol.
i-SCSI is a cheap and easy protocol that permits Application Servers to use remote hard disk drives as if they were directly connected to the board with a classical flat cable.
The darker RJ-45 connector on the left is another ethernet port, but this one permits IP management of the storage through the ISM Integrated Storage Manager application.
The port with the green bullet is the serial consoles: it is a technical access used for very rare operations not embedded in the graphical tool: e.g. assign the controller IPs.