How to speed up rsync?

Question

I'm running rsync to sync a directory onto my external USB HDD. It's about 150 gigs of data. 50000+ files I would guess.

It's running it's first sync at the moment, but its copying files at a rate of only 1-5 MB/s. That seems incredibly slow for a USB 2.0 enclosure. There are no other transfers happening on the drive either.

Here are the options I used:

rsync -avz --progress /mysourcefolder /mytargetfolder

I'm running Ubuntu Server 9.10.

Solution 1

For the first sync just use

cp -a  /mysourcefolder /mytargetfolder

rsync only adds overhead when the destination is empty.

also.. the -z option is probably killing your performance, you shouldn't be using it if you are not transfering data over a slow link.

Solution 2

If you're using rsync with a fast network or disk to disk in the same machine,

not using compression -z

and using --inplace

speeds it up to the performance of the harddrives or network

compression uses lots of CPU

not using inplace makes the harddrive thrash alot (it uses a temp file before creating the final)

compression & not using inplace is better for doing it over the internet (slow network)

NEW: Be aware of the destination... if there is NTFS "compression" enabled... this severely slows down large files (I'd say 200MB+) rsync almost seems stalled, it's caused by this.

Solution 3

Use the -W option. This disables delta/diff comparisons. When the file time/sizes differ, rsync copies the whole file.

Also remove the -z option. This is only useful for compressing network traffic.

Now rsync should be as fast as cp.

Solution 4

First - the number of files in this case is going to be a major factor. It's an average size of 3MB each. There's probably an io bottleneck influencing the speed in the OP's case. More here - that's a pretty dry read, but the cover picture is worth it.

So, using rsync to copy to an empty directory? Here are some ways to speed it up:

1. No -z - definitely don't use -z as in the OP.
2. --no-compress might speed you up. This could have the biggest impact... my test was 13,000 files, total size 200MB, and using rsync 3.1.3. I synced to a different partition on the same internal SSD drive. With --no-compress, I get 18 MBps, and without it I get 15 MBps. cp, by the way, gets 16 MBps. That's a much smaller average file size though. Also - I can't find any documentation for --no-compress. I learned about it from this post on stackexchange.com.
3. -W to copy files whole - always use this if you don't want it to compare differences; never mind that the point of rsync is to compare differences and only update the changes.
4. -S to handle sparse files well - can't hurt if you don't have sparse files.
5. --exclude-from or something similar to exclude files you might not need will cut down the time, but it won't increase your transfer speed.
6. It's possible if you send the output to a file like this rsync -a /source /destination >/somewhere/rsync.out 2>/somewhere/rsync.err - the first > basically prints a file with all the stuff you would normally see, and the 2> refers to error messages.
7. Finally, running multiple instances of rsync for different parts of your transfer could be a big help.

My command would be:

rsync -avAXEWSlHh /source /destination --no-compress --info=progress2 --dry-run

If all looked well, I'd delete "--dry-run" and let it go. A, X, and E cover extended attributes and permissions not covered by -a, l is for soft links, H is for hard links, and h is for human readable.

Updating an already synced directory on a USB drive, or the same drive, or over a network, will all require different rsync commands to maximize transfer speed.

Bonus - here's the rsync man page, and if you want to test your hard drive speed, bonnie++ is a good option, and for your network speed, try iperf.

---

*The post is almost ten years old, but search engines sure like it, and I keep seeing it. It's a good question, and I don't think the top answer to "how to speed up rsync" should be "use cp instead."

Solution 5

You definitely want to give rclone a try. This thing is crazy fast :

$ tree /usr [...] 26105 directories, 293208 files

$ sudo rclone sync /usr /home/fred/temp -P -L --transfers 64

Transferred: 17.929G / 17.929 GBytes, 100%, 165.692 MBytes/s, ETA 0s Errors: 75 (retrying may help) Checks: 691078 / 691078, 100% Transferred: 345539 / 345539, 100% Elapsed time: 1m50.8s

This is a local copy from and to a LITEONIT LCS-256 (256GB) SSD.

You can add --ignore-checksum on the first run to make it even more faster.

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Comments

[Admin]

are you sure you're getting a USB2 connection? does a (non-rsync) copy or other write operation run at normal speeds? if not, have you tried a copy/other write op with another USB port/cable?

[Admin]

See also serverfault.com/questions/43014/… - there people also propose using two piped tar commands or cpio.

[Admin]

Like @tom-hale pointed out in your case the compression makes no sense, because you copy between local filesystems. Compression only makes sense when you copy between two hosts over a network.

[msanford]

rsync is so called because it's for remote synchronization and is not really appropriate for a locally-connected volume for this very reason.

[Blaisorblade]

It's supposed to be usable also for local transfers, and it's much more flexible. It's only possibly overkill for the first sync.

[Speederer]

Minor note: -z is only useful for low speed network traffic. If your network is fast enough, it'll slow things down, since you'll be limited by CPU.

[djhworld]

These tips vastly sped up the transfer of my files between two NAS devices, thanks!

[Jesse the Wind Wanderer]

rsync is also a one way sync. Very good for backing up to a server or from a server. However, if you want local TWO-Way sync to a removable drive, you may want to check out csync csync.org/get-it not to be confused with csync2 which is a completely different project.

[Scott Kramer]

NTFS compression is slowwww on big files

[GuoLiang Oon]

but note that according to the man page says for -W: "This is the default when both the source and destination are specified as local paths, but only if no batch-writing option is in effect."

[Anthony]

I don't see anything about '--inline' on the man page

[editor]

rsync -avz --progress /mysourcefolder/ /mytargetfolder or you'll get a copy of mysourcefolder inside of mytargetfolder rather than mirroring the contents

[Scott Kramer]

It's '--inplace'

[oemb1905]

This answer does not answer the question. The question was about how to optimize rsync - not replace it with the cp command.

[user2480144]

In respect of item 7) I could improve a lot more the performance using a traditional HDD as the source, by extending read-ahead buffer using "blockdev --setra 8192 /dev/sdX". So I intend to reduce head seeks.

[Sammy Guergachi]

I've found that S (handling Sparse files) is actually slow. Removing it made it much faster

[markhahn]

--inplace will only help if you already have a file there, and it's mostly the same as the source. otherwise, rsync defaults to an atomically safe method (destination tmp named, then mv into place.)

[Chris L. Barnes]

--no-compress is not mentioned in the rsync man page.

[Mila Nautikus]

--transfers 64 is a recipe for file fragmentation (no?)

[logoff]

-W was the key in my case (over local network). I went from ~3.5 MB/s to ~35 MB/s. a 10x factor!!

[robertspierre]

You are not explaining anything of what's happening here nor why this is a better solution thatn OP's

[robertspierre]

The -W also worked spectacular for me. 10x factor exactly like logoff. Especially super-useful for big files!

[matson kepson]

you are right @raffaem, i have added some explanation on switches, cheers

[systemexit]

The literal text --no-compress does not appear in the man page because it falls under the generic --no-OPTION

[Illya Moskvin]

Other answers here already contain good optimizations. This is one I haven't seen mentioned yet. For context, I invoked rsync in a "User data" script that runs on AWS EC2 instance startup. The user data script writes to /var/log/cloud-init-output.log. I was syncing about 25,000 files, so it needed to write 25K lines to the log file. Running rsync silently took about 12 seconds. Running the same command with -v took 100 seconds. Huge difference!

[Anirudh Ajith]

Thanks a lot! This gave me a 12x speedup!