fcp
Dev tools
file copy utility
SHOW HN2021
How HN took it
2 positive, 23 neutral or asking, 0 mixed, 13 critical, out of 38 comments about the project. Thread score -0.30.
Performance: 1 for, 8 againstIdea: 1 for, 3 against
The thread, comment by comment
Each row is a top-level comment and its replies, in HN's order. Select a cell to open that comment on HN.
positive neutral or mixed critical about another commenter or something else the maker
What HN said
What people liked
Large speedup over cp on NFS and some benchmarks
From 1 comment
I just tried this going between my 2 servers with NFS, as compared to cp, rsync, and rclone. This tool wins by >2x. Great work! ~1.5Gbps vs ~3-4Gbps.
virtuallynathan on HN
Objections
Multi-threaded copying is slower on spinning hard drives
From 2 comments
It looks like this is using multiple threads to copy files. That's fine for NVMe which tends to achieve more throughput with higher queue depths. But it will degrade performance…
the8472 on HNMy experiments confirms your analyze. On a SATA hard drive using ext4, I copied a directory with a large hierarchy of file and 216MB overall. After 2 warm-ups, I launch this…
idoubtit on HN
Lacks most of cp's options
From 2 comments
For SSDs this is probably the right thing (maybe use uring tho?) For hard drives this is the opposite of what you want. For hard drives, especially when copying large trees, you…
formerly_proven on HNDefinitely valid points, as I mentioned in a comment below I'll be updating the README to mention this is geared towards systems with SSDs. As for lacking most of cp(1)'s…
Svetlitski on HN
Saturating CPU with threads is undesirable for utility tools
From 1 comment
Why do people think it is acceptable for utility programs like file copies to launch many threads and saturate my CPU? It's usually the case that there are many things being done…
kccqzy on HN
Speed claim based on core count is misleading since disk IO is the bottleneck
From 2 comments
> The primary reason is that it uses all of your computer's available cores to walk through directories and copy files, effectively speeding things up by a factor directly…
jjav on HNThe only thing I'd like "new" in cp is an optional progress indicator, for large files Btw, copying files is mostly bound by disk speed (or network if share), not so much by CPU,…
gregoriol on HN
Requests
Benchmarks on other filesystems
From 1 comment
What filesystem on Linux? Show us some benchmarks on other filesystems.
cratermoon on HN
Man page documentation
From 1 comment
My only gripe with those new unix tools is that many of them don't come with a man page, even though they have essentially the same information elsewhere So, perhaps, take a look…
nextaccountic on HN
Support for reflinks and deduplication
From 1 comment
Does this support reflinks on filesystems that support deduplication? (like cp --reflink)
nextaccountic on HN
Progress indicator for large files
From 1 comment
The only thing I'd like "new" in cp is an optional progress indicator, for large files Btw, copying files is mostly bound by disk speed (or network if share), not so much by CPU,…
gregoriol on HN
Questions
Why is it faster than cp?
From 1 comment
_Why_ is it faster? (particularly on Linux, I see you're using syscalls on mac that mac's cp doesn't, since apple doesn't really maintain their unix userspace)
jepler on HN
Does it sacrifice fsync durability?
From 1 comment
Does this software gain any speed by sacrificing any safety? As in, does it switch off fsync in any way? Are the files guaranteed durable by the time the software terminates?
mnw21cam on HN
Which filesystems are supported?
From 1 comment
What file systems are supported here?
slava_kiose on HN
Alternatives named
GNU cp with reflink options
From 2 comments
> The massive difference in performance in this case is due to fcp using fclonefileat and fcopyfile under the hood GNU Coreutils' cp, the thing you use on most GNU/Linux systems,…
kazinator on HNDoes this support reflinks on filesystems that support deduplication? (like cp --reflink)
nextaccountic on HN
rsync, rclone
From 1 comment
I just tried this going between my 2 servers with NFS, as compared to cp, rsync, and rclone. This tool wins by >2x. Great work! ~1.5Gbps vs ~3-4Gbps.
virtuallynathan on HN
uutils coreutils rewrite
From 1 comment
I would argue that "the easy parts" of cp account for a very significant fraction of its usage (i.e. copy some files/directories without any other options). The idea with fcp is…
Svetlitski on HN
wcp (io_uring based copy tool)
From 1 comment
Not a question, but I made a similar tool in c++[1], for Linux only using io_uring, and a blog post explaining its internals [2]. I'll definitely have a look some time soon, I'd…
wheybags on HN