https://github.com/pjd/openzfs/commit/184c9e78733381c7cc4f0b18e9d6819a6f3c1c66 BRT based reflink implementation (copy_file_range) for openzfs , about to PR hopefully
GitHub
Implementation of block cloning for ZFS. · pjd/openzfs@184c9e7
Block Cloning allows to manually clone a file (or a subset of its
blocks) into another (or the same) file by just creating additional
references to the data blocks without copying the data itself.
...
blocks) into another (or the same) file by just creating additional
references to the data blocks without copying the data itself.
...
https://github.com/openzfs/zfs/pull/13392 openzfs 基於 BRT 的 block cloning (reflink) 終於 merge 了
GitHub
Block Cloning by pjd · Pull Request #13392 · openzfs/zfs
Motivation and Context
Block Cloning allows to clone a file (or a subset of its blocks) into another (or the same) file by just creating additional references to the data blocks without copying the...
Block Cloning allows to clone a file (or a subset of its blocks) into another (or the same) file by just creating additional references to the data blocks without copying the...
fc fs筆記
https://blog.stuffedcow.net/2019/09/hard-disk-geometry-microbenchmarking/
（自己的筆記經常找不到鏈接於是記錄一下） 通過 microbenchmarking 測量 LBA 間跳轉消耗的 seek time 來測量現代 hdd 上 LBA 的具體物理扇區映射關係。可以看出近現代硬盤上扇區佈局已經發展到傳統的柱面之類的概念沒有什麼實際意義了
Forwarded from 糊锅
A kernel without buffer heads
https://lwn.net/SubscriberLink/930173/c288defca11561e8/
https://lwn.net/SubscriberLink/930173/c288defca11561e8/
lwn.net
A kernel without buffer heads
No data structures found in the Linux kernel — at least, in any version
that escaped from Linus Torvalds's development machine — are older than the
buffer head. Like many other legacies from the early days of Linux, buffer
heads have been targeted for removal…
that escaped from Linus Torvalds's development machine — are older than the
buffer head. Like many other legacies from the early days of Linux, buffer
heads have been targeted for removal…
fc fs筆記
A kernel without buffer heads https://lwn.net/SubscriberLink/930173/c288defca11561e8/
關了 buffer heads 支持會得到一個有 xfs btrfs 沒有 ext4 f2fs jfs ntfs3 fat 和 dm 的內核
https://youtu.be/NtkKHhXf3V4 linux nvme and block layer
YouTube
Linux NVMe and block layer status update (SDC 2019)
This talks explains the exciting new features in the Linux NVMe driver and software target in the last two years, as well as the
relevant block layer changes to support these features.
Presented by Christoph Hellwig, Kernel Hacker
Learn More:
SDC Website:…
relevant block layer changes to support these features.
Presented by Christoph Hellwig, Kernel Hacker
Learn More:
SDC Website:…
https://lwn.net/Articles/888715/ Linux readahead
lwn.net
Readahead: the documentation I wanted to read
The readahead code in the Linux kernel is nominally responsible for
reading data that has not yet been explicitly requested from storage,
with the idea that it might be needed soon. The code is stable, functional, widely
used, and uncontroversial, so it…
reading data that has not yet been explicitly requested from storage,
with the idea that it might be needed soon. The code is stable, functional, widely
used, and uncontroversial, so it…
https://www.vidarholen.net/contents/blog/?p=479 tl;dr: dd works for reading and writing disks, but it has no "low level I/O" capabilities that make it more suited for this than any other shell utility. Like cat you should use it where it makes sense, e.g. to take advantage of its wide array of options, rather than try to ensure that all disk related commands begin and end with dd out of fear and superstition.
https://lore.kernel.org/linux-btrfs/20231217165359.604246-1-hch@lst.de/ host-aware SMR hdd 從 SCSI / ATA 標準中刪掉了(NVMe 標準中沒有加過)，今後就只會有 host-managed 和 device-managed SMR 了。 Linux 內核會把現存少量的 host-aware SMR 設備當作 device-managed SMR （OS 看來是普通的 HDD ）用