Am 24.07.2014 06:47, schrieb Linda Walsh:
Freek de Kruijf wrote:
Op woensdag 23 juli 2014 14:16:40 schreef auxsvr@gmail.com:
On Wednesday 23 of July 2014 10:22:06 Daniel Bauer wrote:
When I copy a file on my server, using drag and drop with two dolphin windows I get a transfer speed of approx. 35-40 kB/s.
When I use rsync to copy the same files I get a speed of approx. 85-90 kB/s.
Where does this difference come from? Maybe rsync uses compression of the data?
On a local copy or local network, that usually slows down transfers.
On might ask why rsync is so slow -- copying 800G from 1 partition to another via xfsdump/restore takes a bit under 2 hours, or about 170MB/s, but with rsync, on the same partition with rsync transfering less than 1/1000th as much (700MB), it took ~70-80 minutes... or about 163kB/s.
That's on the same system (local drive -> another local drive)
Transfer speeds depend on many factors. One of the largest is transfer size (how much transfered with 1 write /read. Transfer 1GB, 1-meg at a time, took 2.08s read, and 1.56s to write (using direct io).
Transfer it at 4K: 37.28s, to read, and 43.02s to write.
So 20-40x can be accounted for just on R/W size (1k buffers were 4x slower).
Many desktop apps still think 4k is a good "read size"
Over a network, causes drop from 500MB/s down to less than 200KB/s (as seen in FF and TB).
Optimal i/o size on my sys is between 16M-256M.
So -- to answer your question, MANY things can affect speed, but I'd look at the R/W size first.
Hi, thanks for the answers the mentioned transfers are over internet with my slow but expensive telefonica-upload... So that it's slow in general is "normal", but copy with dolphin is even slower... In the test case I transferred a very large file (1 GB), with dolphin via fish: and with rsync via ssh: I don't know where to look at R/W size of dolphin, and even less how to set an optimal size (no idea about the pros and cons of changing settings)... I only use dolphin to copy single or just a few files, for mass transfer I always use rsync, which seems more reliable to me. But especially with large files and the slow connection I have, it makes quite a difference when dolphin only uses half of the available... Someone asked for the first top lines (sorry I accidentally deleted the post...), so here they are:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 6135 daniel 20 0 1404m 237m 72m S 11.6 1.5 18:58.36 plasma-desktop 6124 daniel 20 0 929m 169m 75m S 9.0 1.1 303:12.27 kwin 5742 root 20 0 222m 136m 57m S 4.3 0.8 945:07.48 Xorg 21609 daniel 20 0 351m 27m 9448 S 1.3 0.2 0:02.15 kio_fish 21595 daniel 20 0 618m 58m 29m S 0.7 0.4 0:03.19 dolphin 21610 daniel 20 0 33672 2748 2140 S 0.7 0.0 0:00.48 ssh 11 root 20 0 0 0 0 S 0.3 0.0 5:13.36 rcu_preempt 5997 daniel 20 0 23844 2364 836 S 0.3 0.0 0:08.38 dbus-daemon 21425 root 20 0 0 0 0 S 0.3 0.0 0:00.28 kworker/1:1 21701 root 20 0 9924 1560 1016 R 0.3 0.0 0:00.05 top 1 root 20 0 45976 4844 2172 S 0.0 0.0 0:02.03 systemd
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