Linux Plumbers Conference 2022

Session

Zoned Storage Devices (SMR HDDs & ZNS SSDs) MC

Sep 14, 2022, 10:00 AM

"Meeting 1&2" (Clayton Hotel on Burlington Road)

314. Zoned MC Conference Kick Off

Adam Manzanares (Samsung Electronics), Matias Bjørling (Western Digital)

9/14/22, 10:00 AM

Welcome and kick off presented by Adam and Matias!

312. A zone-aware cache system for distributed databases

Kuankuan Guo

9/14/22, 10:05 AM

Modern analytical distributed database platform requires massive data from remote filesystems(e.g. HDFS). A cache layer is necessary to eliminate the network bottleneck by caching data items with smaller granularity (e.g. 64KB ~ 128KB).

There are three major challenges to implementing such a cache system:
1. Predictable latency (latency spike is not acceptable)
2. Good enough user-side...

42. SSDFS: ZNS SSD ready file system with zero GC overhead

Viacheslav Dubeyko (ByteDance)

9/14/22, 10:25 AM

The architecture of SSDFS is the LFS file system that can: (1) exclude the GC overhead, (2) prolong NAND flash devices lifetime, (3) achieve a good performance balance even if the NAND flash device's lifetime is a priority. The fundamental concepts of SSDFS: (1) logical segment, (2) migration scheme, (3) background migration stimulation, (4) diff-on-write. Every logical block is described by...

130. Improving data placement for Zoned Linux File systems

Hans Holmberg

9/14/22, 10:45 AM

In this talk I'll present what I've learned from building ZenFS, a user-space
RocksDB file system for zoned block devices, and what features could be transferable to kernel file systems.

I'll go over the goals and high-level design of zenfs, focusing on the extent
allocator, present what performance gains we've measured[2] and what the trade-offs are when constructing a file system for...

131. Object caching on Zoned Storage

Hans Holmberg

9/14/22, 11:05 AM

Object caching is a great use case for SSDs but it comes with a big device write amplification penalty - often as much as 50% [1] of the capacity is reserved for over-provising to reduce the impact of this on conventional SSDs.

There is a great opportunity to adress this problem using zoned storage, as the garbage collection can be co-designed with the cache eviction policy.

Objects...

152. Supporting non-power of 2 zoned devices

Pankaj Raghav

9/14/22, 11:45 AM

The zone storage implementation in Linux, introduced in v4.10, first targeted SMR drives with a power of 2 (po2) zone size alignment requirement. The newer NAND-based zoned storage devices do not naturally align to po2, so the po2 requirement introduces a gap in each zone between its actual capacity and size. This talk explores the various efforts[1] that have been going on to allow non-power...

153. Zonefs: Features Roadmap

Damien Le Moal (Western Digital)

9/14/22, 12:10 PM

This presentation will discuss planned new features and improvements for the zonefs file system: asynchronous zone append IOs, relaxing of O_DIRECT write constraint and memory consumption reduction. Feedback from the audience will also be welcome to discuss other ideas and performance enhancements.

176. Btrfs RAID on zoned devices

Johannes Thumshirn (Western Digital Corporate)

9/14/22, 12:35 PM

Currently there is no possibility to use btrfs' builtin RAID feature with zoned block-devices, for a variety of reasons.

This talk gives a status update on my work on this subject's matter and possibly a roadmap for further development and research activities.

211. Experiences implementing zonefs support in ZenFS

Jorgen Hansen (WDC)

9/14/22, 1:00 PM

The talk will cover the main challenges in porting an zoned block device aware application using raw block device access (ZenFS using libzbd) to zonefs. In addition to this, a performance comparison between ZenFS using zbdlib and zonefs will be presented.