Drobo

Optimal block size

Drobo recommends that I let my DroboPro format new drives. DroboPro formatter my 2TB drives using 4K blocks. On traditional drives, I have chosen to use 16K or 64K blocks (clusters) because my files are mostly large media files.

If I reformat a DroboPro drive using Windows tools, will that affect performance?

Try it and report back.

That’s a bit problematic, with terabytes of data already on the device.

I was hoping the folks at Data Robotics could tell if DroboPro is indifferent to cluster size. NTFS performance will increase with larger cluster size and my file sizes.

Mark F have commented on this in the performance thread:
"SuiteB - DroboPro doesn’t perform well on small block sizes. Make it 128-256K or larger. Here is a review with more information http://www.d3dphotography.com/blog/index.php/2009/07/16/data-robotics-drobopro-review/ "

Sounds interesting if the DroboPro defaults to 4k if DRI reccomends 128-256K…

Right, I read that, but I thought he was talking about benchmark block sizes, not file system cluster sizes.

Anyway, NTFS only supports up to 64k clusters.

Ah, you are right. I didn’t really thing other than that they are a bunch of Mac-freaks and I have no clue about cluster sizes on HFS+ :slight_smile:
Ignore my post.

Unfortunately, at least according to Mark F, there is no way to alter the block size in HFS+, or even see what it is, although some third party disk utilities might tell you, or some forensic tools. At least I’ve never found a way to do so.

But for Windows, I would certainly go into Disk Manager, see what it is now, and try something bigger, at least 4j (the default may be as little as 1K), and keep trying until things bottom out. Windows tends to use rather small blocks, in order to pack small files more tightly, but with terabytes of space available you are probably more concerned about efficiency.

Of course, if you already have the Drobopro half full, this may be painful, but you might consider buying two or three cheap 500GB disks, or use some you have lying around for such testing.

In any case, please report your findings.

At the very least when you create RAIDs in OSX’s setup it allows you to pick block sizes.

Ok, I moved some 2TB of files around (took 20+ hours), reset DroboPro and formatted via Windows with 64K cluster size instead of the default 4K. Large file copy progressed at 25MB/s, so no improvement here. Went back to default, DroboPro formatted disks, with somewhat better results (see thread on performance).

I found early on it’s best to let Drobo manage its own drives in its own way, and for me to stay out of the micro-manage-tweak-this-mode I sometimes get into.

Here I find myself staring at my previous post…looking for answers about “tweaking” the cluster size of my DroboV2. Guess I’d better take my own advice and leave it alone!