Where did all those disks come from?

October 1, 2014

(Another word for “FlexConfig”)

I’m doing it again … writers block so back to explaining a feature of our cards that you may not be aware of.

In the BIOS of our controller (under “Controller Settings/Controller Configuration/Controller Mode”) we have added several new options. Series 8 gets one more option than Series 7 just for confusion sake. Before I go into the details of the modes, I need to explain metadata.

Metadata is the area of the disk where we store our RAID information – who/what/where/why and how. It is created by “initializing” a disk. So when you initialize a disk it wipes out any previous metadata, and creates a new clean structure for the controller to store the RAID information on the disk.

The opposite to this is “uninitialise”. This removes metadata completely, leaving a blank clean disk that is for all intents and purposes not part of anything to do with RAID.

These two differences are important. Keep it in mind when reading the following breakdown of what the different modes do …

RAID: expose Raw

This setting allows you to make RAID arrays from available disks, but if you don’t include a disk in a RAID array, and it has no metadata on it (ie a brand new disk), then the card will show it through to the operating system. This is the default and the one that is catching people out.

RAID: hide RAW

This setting allows you to make RAID arrays from available disks, but if you don’t include a disk in a RAID array it is hidden from the operating system. This is in fact how our cards have behaved since the dawn of time.

HBA

This turns off all RAID, and turns the card into an HBA (host bus adapter). How why would you want to do that? Beats me but someone obviously wants to so we put this feature in there for them.

Auto Volume

This one is a doozy. When you set the card into this mode, it automatically takes all “raw” (uninitialized) disks and turns them into simple volumes (basically single disk raid arrays with read and write cache enabled). This is very handy because when a drive fails, and you replace it, the controller will automatically turn that new drive into a simple volume as well.

Simple Volume

I struggled with this one for a while, until a wise sage from the US explained it to me. This mode allows you to manually create simple volumes. That is your only choice. However it lets you break the 64-RAID/volume barrier our cards have. In any of the above modes, you can only have up to 64 RAID arrays/volumes on a single card. If you need more simple volumes than that you can change to simple volume mode, and manually create up to 256 simple volumes. Glad I don’t have the job of doing that J

Usage

So where and how and why does all this get used. For the majority of users you won’t even touch this mode, so you’d think it doesn’t matter, but there is a sting in tail for every feature.

When you build a new server, if you do it like I do, I generally build the array I’m going to put my OS on, then worry about the other arrays later. If these happen to be on separate disks, then what will happen is …

  1. Make RAID array on 2 disks and install OS (the rest of my brand new disks are just sitting there for me to make a RAID array later in maxView)
  2. Pop your nose into Windows disk management and get a surprise. There is your RAID array, and also every other disk connected to your controller … which is a bit confusing because you may not have seen this behavior before.
  3. Try to make a raid array from those disks in maxView … you can’t. You need to “initialize” a disk (to put the metadata on it) before you can include the disk in a RAID array (which can be done from within maxView).

Confused? Possibly, but it’s pretty simple after you’ve been surprised the first time. I was going to continue writing for another 4 pages to explain all the little differences and intricacies of this, but I’m too lazy do will just tell you to talk to your Adaptec support rep or FAE if you want to know more about this feature.

While I might sound a bit sarcastic about this feature – it has some amazing time savings and possibilities/options for users to create quite complex data structures, so I’d suggest learning a bit more about “FlexConfig”.

Ciao
N

 

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