Large Block Disks (LBD)

Large Block Disks (LBD)

November 21

The average computer uses a hard with a 512B sector size, or 2048B of user accessible data.  This is enough for typical everyday use and to be honest, that’s about as far as most people go when they think about disk use and storage optimization.  However, this is my opportunity to share some HDD minutia and broach the subject of Large Block Disks (LBD) so bear with me.

Multiple-terabyte drives are becoming more and more common.  These newer HDD’s use advanced format sectors currently hovering around 4096B sector sizes.  What does this mean to you?  Well, in the general sense it means you can store more stuff.  Of course, HDD’s measured in Terabytes will store more information than those measured in Gigabytes.  That much should be obvious, but what may not be obvious is that when it comes to optimizing space a disk drive segmented in 4096B sector sizes will typically store more data than a drive segmented in 512B sectors.  The reason is that there is less wasted space.

The data (logical records) are written to the HDD as blocks (physical records).  These blocks can be grouped together more frequently in larger block sizes than they can in smaller block sizes.  This is how larger block sizes have less wasted space, because they can more efficiently use the same available physical space. Add to this the idea that more frequent read/writes to smaller block sizes means more wear and tear on the drive platters, motor, and heads and we might be able to infer that larger block sizes translates to longer HDD lifetimes and the accompanying cost savings.  Hopefully all of these small savings in optimized space and minimized wear translate into a significant dollar savings to your bottom line.  If not, then well… at least you have been introduced to these concepts, and there’s always the opportunities Solid State Drive’s present with their 4K paging!