So, as almost all of you know by now, Linux Journal is no more. But that does not mean that my writing has stopped. In fact, a new piece just landed the website of ADMIN Magazine called “Linux Device Mapper Writecache.” ADMIN Magazine is owned by Linux News Media, owners of Linux Magazine. Anyway, look forward to more of my submissions popping up in both their website and in their magazine pages. Anyway…
Solid State Drives (SSDs) brought performance to the forefront of computing technologies, and their adoption is increasing not only in the data center but also in consumer-grade products. Unlike its traditional spinning hard disk drive (HDD) counterpart, SSDs comprise a collection of computer chips (non-volatile NAND memory) with no movable parts. Therefore SSDs are not kept busy seeking to new drive locations and, in turn, introducing latency. As great as this sounds, SSDs are still more expensive than HDDs. HDD prices have settled to around $0.03/GB; SSD prices vary but sit at around $0.13-$0.15/GB. At scale, that price gap makes a world of difference.
To keep costs down and still invest in the needed capacities, one logical solution is to buy a large number of HDDs and a small number of SSDs and enable the SSDs to act as a performant cache for the slower HDDs.
Again, you can read the full article here.