For over 30 years, hard drives have designated the smallest storage location as 512 bytes. In January 2011, all major hard drive manufactures began shipping their hard drive platforms using a new standard called Advanced Format. To aid in the transition, these new hard drives provide a 512 byte emulation mode that allows the drives to advertise themselves as a 512 byte addressable devices. This can severely impact write performance resulting in the need for read-modify-write operations for any misaligned or partial writes that are issued.
The problem is not limited to just physical hardware. Other storage platforms may also provide LUNs (logical unit number) that presents themselves as a 512 byte addressable devices when, in fact, they use a 4K sector size internally. Although ZFS has built-in support for 4K sectors, it has no automatic way of dealing with the lies that the storage devices tell. This talk will focus on the methods that have been developed to work around the lies that hard drive storage platforms tell and will discuss the challenges and drawbacks that come with using 4K sectors.
On illumos Day http://zfsday.com/about-illumos-day/, Joyent’s own Ben Rockwood http://cuddletech.com/blog/ gave us an in-depth look at the tools and techniques he uses to manage Joyent’s public cloud http://joyent.com/ on SmartOS http://smartos.org/, covering everything from monitoring to configuration management and troubleshooting. Here’s video of the complete talk: 55 minutes of deep devops goodness, packed full of knowledge – and humor.
In 2008, the ZFS Storage Appliance (nee the Sun Storage 7000) was one of the first architectures to add flash SSDs between the existing tiers of disk and memory. The Hybrid Storage Pool (HSP) offered completely new economies, but with both known and unknown idiosyncrasies. Adam Leventhal, the inventor of the HSP, will talk about their functionality and utility, pitfalls and shortcomings, as well as the next steps for ZFS amidst an ever changing landscape of technologies and economics.
