Rsync error unexplained error code 255 at io c

My server backup task is failing with this error. Please fix!
rsync: [sender] write error: Broken pipe (32)
rsync error: unexplained error (code 255) at io.c(837) [sender=3.1.0]

That was a recent request we received as part of our Server Management Services.

Often, this rsync error happens due to bad ssh settings on the server.

Today, let’s get into the details and see how our Support Engineers fix rsync error code 255.

How to use rsync?

Basically, Rsync is a Linux-based tool for synchronizing documents between remote and local servers.

It becomes really popular as it will only sync or copy the changes from source to the destination. Thus it saves the effort of copying the whole file. Consequently, the command ultimately reduces the amount of data sent over a network.

A sample rsync over ssh command to perform backups to a remote server looks as

rsync -azLvv --progress -e 'ssh -p22 -vvv' --exclude 'xxx' /home/user/ server.tld:/backup/DIR

It copies the folder /home/user to the remote server.

However, an error may occur while using the rsync command.

How we fix common rsync errors

At Bobcares, where we have more than a decade of expertise in managing servers, we see many customers face problems while running the rsync command.

Now let’s see the major reasons for rsync errors and how our Support Engineers fix the top errors.

1. Bad ssh configuration

Recently, one of our customers had a problem while executing the rsync command. He got an error like below

rsync: [sender] write error: Broken pipe (32)
rsync error: unexplained error (code 255) at io.c(837) [sender=3.1.0]

Broken pipe error most likely means that the server hit a timeout in SSH. It generally means that there is a bad setting in the ssh configuration file.

Then, our Support Engineers first check whether the ssh configuration was set up correctly. Most of the time customers may forget to set up the settings in the local ~/.ssh/config file.

This will create problems like timeout while synchronizing large files. Here, the fix was to add the keep-alive options. So, we added the following lines in the local ~/.ssh/config file.

Host *
ServerAliveInterval 30
ServerAliveCountMax 6

Again, on the remote server, we added these in the /etc/ssh/sshd_config file.

ClientAliveInterval 30
ClientAliveCountMax 6

That fixed the error and resumed the rsync process.

2. Incorrect Syntax

Similarly, another customer has requested us to solve a rsync error such as Rsync stopped working and returns “rsync error: unexplained error.

On investigating, our Support Engineers found the detailed error as:

Permission denied (publickey).
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(605) [sender=3.0.9]

Also, because of the use of bad syntax as misplaced double quotes ” in the command, this error occurred. So, we corrected as below.

rsync -rdtvu --delete -e "ssh -p 22 -i /path/to/sshkey" /media/local/xxx/ user@1xx.21x.0.1:/xxxx/remote/dir/

Hence, the problem was fixed. When the server uses a non-standard SSH port, we always take special care in ensuring the correct setting in the port.

3. Firewall settings

Often firewall settings also create problems and report Rsync error code 255.

In such cases, our Dedicated Engineers first run the rsync command in verbose mode. It usually shows the port restrictions. A sample output appears as:

[root@srv]$ sudo ssh -vvv server@1xx.1yy.1.102
debug1: Reading configuration data /etc/ssh/ssh_config
debug2: ssh_connect: needpriv 0
debug1: Connecting to 1xx.1yy.1.102 [1xx.1yy.1.102] port 22.
debug1: connect to address 1xx.1yy.1.102 port 22: Connection refused
ssh: connect to host 1xx.1yy.1.102 port 22: Connection refused

Then, we make adequate modifications to the firewall. For already blocked IP addresses, we unban in Fail2ban using the following command.

fail2ban-client set JAILNAME unbanip IPADDRESS

[Need assistance to fix rsync errors? We’ll help you.]

Conclusion

In short, rsync error code 255 may occur if the server has a bad ssh setup or if the rsync command has syntax errors. Today, we saw the top reasons for the rsync error and how our Support Engineers fixed it.

var google_conversion_label = «owonCMyG5nEQ0aD71QM»;

Good day everyone. I’m trying to rsync to my Manjaro server over ssh. Nothing fancy, just a single PNG in order to verify that it works. I’m using a basic password authentication in order to verify that I can get it functioning before I start packing on extra security.

rsync -v -e ssh /home/john/rsyncdemo/rsyncdemo2/saved.png sshuser@192.162.2.187:/home/sshuser/Desktop/rsyncdemo/rsyncdemo2/saved.png

When I do that, about 10 seconds go by until I receive the following error.

ssh: connect to host 192.162.2.187 port 22: Connection timed out
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(226) [sender=3.1.2]

I’m no stranger to ssh but this is something beyond my modest understanding of the deep inner workings. I googled the problem but I didn’t want to throw arbitrary solutions at my system without first understanding the problem. I’ll explain what I have done in order to gather more information. I have 3 systems.

1. Win10-PC with Cygwin (fully updated) (Atheros Wireless)
2. Arch-Laptop (fully updated) (Atheros Wireless)
3. Manjaro-Server (fully updated) (Wired)

+router

• ASUS RT-N10P

First thing I checked was sshd. Enabled and restarted sshd on all 3 machines. It’s worth noting that my Manjaro is a brand spanking new install. Arch has been modified but the system is very minimal. Cygwin is also new but It’s been awhile since I reinstalled Windows and I have a few things running in the background. I also forwarded the ports and disabled the firewall on my router.

Ran the three commands.

ssh sshuser@192.162.2.187

rsync -r /cygdrive/c/Users/John/Desktop/rsyncdemo/ /cygdrive/e/rsyncdemo/

scp /cygdrive/c/Users/John/Desktop/rsyncdemo/rsyncdemo2/saved.png sshuser@192.168.2.187:/home/sshuser/Desktop/rsyncdemo/rsyncdemo2/

All of these commands work. What that means is that: logging into the machine via ssh works, copying files to the server works and rsync works. The problem exists when I try to rsync via ssh. One of two possibilities exists. Either there is something wrong with the server, or I missed some fundamental step in configuring ssh on both client computers. It’s more likely the former. Like I said, I had prior experience setting up ssh and it wasn’t that hard the first few times. I started by checking the ssh and rsync versions I was running.

Win10-PC (sshd enabled and started)

OpenSSH_7.5p1, OpenSSL 1.0.2k  26 Jan 2017

Arch-Laptop (sshd enabled and started)

OpenSSH_7.5p1, OpenSSL 1.1.0f  25 May 2017

Manjaro-Server (sshd enabled and started)

OpenSSH_7.5p1, OpenSSL 1.1.0f  25 May 2017

All 3 machines

rsync  version 3.1.2  protocol version 31
Copyright (C) 1996-2015 by Andrew Tridgell, Wayne Davison, and others.
Web site: http://rsync.samba.org/
Capabilities:
    64-bit files, 64-bit inums, 64-bit timestamps, 64-bit long ints,
    socketpairs, hardlinks, symlinks, IPv6, batchfiles, inplace,
    append, ACLs, xattrs, iconv, symtimes, prealloc

You may have noticed the Cygwin version of openssl is not as high as the other two. I don’t think this could cause the problem since Arch also can not connect to the network. Like I said before, Either there is something wrong with the server, or I missed some fundamental step in configuring ssh on both client computers.

I also read this thread but I’m not sure if the chosen answer wants me to configure the ssh_config file on the host of the client. In either case, a simple png should not take this long to rsync so I doubt it has anything to do with the problem but I’ll leave it here in just in case

rsync timed out

If you have an answer off the top of your head, awesome. If you don’t, then posting something that can help further isolate the problem would be equally appreciated. Thank you so much for your help.

необъяснимая ошибка rsync (код 255) в io.c

Я использовал скрипт для выполнения rsync в sudo crontab . Сценарий выполняет двухстороннюю rsync (от сервера A к серверу B и обратно). После перезагрузки обоих серверов сервер rsync не работает sudo crontab . Я также установил новый cronjob, и он не работает, ошибка:

Однако при запуске из терминала скрипт rync работает, как и ожидалось, без проблем. пожалуйста помоги.

Немного трудно ответить, учитывая почти полное отсутствие соответствующей информации, но, как правило, если команда работает из приглашения, а не из задания cron, это потому, что вам нужно указать полный путь к команде (ям). Задания Cron не имеют нормальной пользовательской среды, что особенно означает, что они не имеют такой же PATH, как у обычных пользователей.

Это происходит, когда в соединении отказано:

SSH: подключиться к хост-порту 2222: соединение отказано

с последующей rsync ошибкой:

rsync: соединение неожиданно закрыто (пока получено 0 байт) [получатель] ошибка rsync: необъяснимая ошибка (код 255) в /SourceCache/rsync/rsync-45/rsync/io.c(453) [получатель = 2.6.9]

Возможные причины:

• В моем сценарии у меня была проблема с брандмауэром. Пробил дыру.
• неверный пароль (вряд ли решит вашу проблему, но вызовет ту же ошибку)

Одной из причин rsync неожиданного закрытия соединения является проблема тайм-аута, особенно когда требуется некоторое время для вычисления контрольных сумм файлов, чтобы проверить различия на удаленном хосте.

Чтобы избежать этой проблемы, вам нужно добавить эти настройки в ваш

/.ssh/config или /etc/ssh/ssh_config :

и необязательно аналогично на удаленном сервере (в /etc/ssh/sshd_config ), например

Источник

Rsync pull — Host key verification failed

I have set up an Rsync job to backup my Nextcloud data folder (NC running on a Raspberry Pi on my local network) to my OMV server. So far I did the following:
— As the Nextcloud data folder is owned by www-data, I created a user «NCrsync» on the Pi and added it to the www-data group
— In the OMV GUI, I created a new SSH key and tried to copy the public key to the Pi which failed as the GUI can’t handle the «Trust this RSA key» prompt. So I created the file /home/NCrsync/.ssh/authorized_keys on the Pi, copied the public key from the OMV GUI and pasted it into this file
— Set up an Rsync job in the OMV gui with the following settings:

However, if I start the Rsync job, it fails:

Please wait, syncing to

Host key verification failed.
rsync: connection unexpectedly closed (0 bytes received so far) [Receiver]
rsync error: unexplained error (code 255) at io.c(235) [Receiver=3.1.2]

The synchronisation has completed successfully.
Done .

What could be the reason for this to fail?

Thank you very much in advance!

Does anyone have an idea?

Well, something went wrong with the key exchange.
The easiest way I know is to simply use
ssh-copy-id NCrsync@

This will allow to connect to your pi without getting asked for the password, until keys change.
If it is only about key verification just log in via ssh once and accept the key so it gets written into know_hosts.
Also you should use lower case user names only, upercase may cause unexpected behaviour.

Also if a windows computer is involved when copying/editing that may have borked some file. Bad coding/newlines.

Be smart — be lazy. Clone your rootfs.
OMV 5: 9 x Odroid HC2 + 1 x Odroid HC1 + 1 x Raspberry Pi 4

I have set up an Rsync job to backup my Nextcloud data folder (NC running on a Raspberry Pi on my local network) to my OMV server. So far I did the following:

I have set up an Rsync job to backup my Nextcloud data folder (NC running on a Raspberry Pi on my local network) to my OMV server. So far I did the following:
— As the Nextcloud data folder is owned by www-data, I created a user «NCrsync» on the Pi and added it to the www-data group
— In the OMV GUI, I created a new SSH key and tried to copy the public key to the Pi which failed as the GUI can’t handle the «Trust this RSA key» prompt. So I created the file /home/NCrsync/.ssh/authorized_keys on the Pi, copied the public key from the OMV GUI and pasted it into this file
— Set up an Rsync job in the OMV gui with the following settings:

However, if I start the Rsync job, it fails:

What could be the reason for this to fail?

Thank you very much in advance!

Did you ever manage to get this to work?

I tried creating an SSH certificate and copy it to the remote server with build in tool. It didn’t work, I am guessing, because of the issue you mentioned. I then tried copying the certificate to authorized_keys of the remote server. Even when I try to SSH to that server it doesn’t work let alone rsync. So I created an SSH key using the old method with ssh-keygen and copied it to the remote server. Validated that I could login without password. Updated everything in Rsync page but I still can’t get Rsync to work.

Please wait, syncing to .

Host key verification failed.
rsync: did not see server greeting
rsync error: error starting client-server protocol (code 5) at main.c(1666) [Receiver=3.1.2]

The synchronisation has completed successfully.

Done .
I tested a manual Rsync command and it seems to run just fine. So I am not sure what’s wrong with the inbuilt tool.

hi
For the archive and others with this problem.

go to the OMV server via SSH as root. «root@ «
connect via SSH to your RSYNC server. «@

«
accept the hostkey by entering ‘yes’
login or disconnect.

The problem is a missing entry for the hostkey in /root/.ssh/known_hosts.
under OMV Rsync runs as root

No luck with this

I have been using OMV 4 for a year and set up a rsync job using the web interface of OMV. Now, with OMV 5.3.5-1, I can’t. I always get the same result:

What I’m trying to set is a rsync job between a PC (Ubuntu 18.04) that I use as a media server and OMV 5 as a remote backup server (local network) installed into a Raspberry with two HD connected by USB. It worked for a long time but now I can’t do it again.

I have also done:

(then, accepted the new fingerprint)

And also the opposite way:

(then, accepted the new fingerprint)

Help anybody? Probably the problem is caused by something obvious but I’ve spent a week trying to figure it out with no luck

Edited once, last by Itookmyprozac ( Mar 1st 2020 ).

Just in case someone arrive here from google. What I have done to solve this (I don’t know if it’s the right thing to do but nobody has told me anything here, so. ) and has worked is:

1. Install samba in my media server (Ubuntu 18.04), from where I want to copy the files to backup. Edit smb.conf to share the directories where the files are.
2. In OMV5, install the remote mount plugin and create the mount points (the directories shared by the media server) and reboot omv. If I don’t reboot it does not work.
3. Create the shared folders in OMV (every folder of the media server that I want to copy and every folder in OMV where I want to put the backup).
4. rsync local folders (the remote points and the local folders where I want to move the backup).

When I used OMV 4 it was way easier to achieve this, but now I have to do all this to get the same results. Not cool

Better solution. Actually, the right solution:

1. Generate certificate ssh (System > Certificates).
2. Copy it into the media server (from where I want to get the copies).
3. Create the rsync jobs (pulling method) selecting ‘Public key’ as a Authentication method and select your certificate.

Edited 2 times, last by Itookmyprozac: Update ( Mar 8th 2020 ).

Источник

Thread: ssh/rsync issues

Thread Tools

Display

ssh/rsync issues

So i recently updated my server from 10.04 to 12.04. I had a script that I used to backup and sync my music from my laptop to the server

rsync and openssh are installed on both machines and googling has turned up nothing so far. any ideas?
I can vnc into the box no problem

Last edited by djyoung4; October 16th, 2012 at 09:52 PM .

Re: ssh/rsync issues

Let’s try to make sure your ssh connection is working OK.

Could you post the result of an ssh connection using the triple verbose option?

Re: ssh/rsync issues

Re: ssh/rsync issues

It look like the ssh service is not running, or set to use another port.

Could you post the results of these commands on the server?

Re: ssh/rsync issues

ha seems to be my problem

Re: ssh/rsync issues

The server side of the openssh package has not been installed yet on the server.

Install it like this:

Let us know how it goes.
Regards.

Re: ssh/rsync issues

I cant seem to figure out where to add the new RSA key. Hopefully someone isn’t really doing something nasty.
edit: I added it in the file and ran the script and still no luck. just gave me some other errors and then closed the terminal before I could copy them

Last edited by djyoung4; October 16th, 2012 at 10:38 PM .

Re: ssh/rsync issues

Either remove the second line of your

/.ssh/know_hosts, or just remove the file (if you don’t ssh to other machines).

Try again, and let us know how it goes.
Regards.

Re: ssh/rsync issues

I think you’re getting that because your system is recognizing that the server has changed and now has a different key. If purge the server’s entry from

/.ssh/known_hosts you should be OK again.

If you can’t decipher which is the server’s (which is not unlikely!) I think you can just purge the whole file. The only downside side that I’ve seen is that you just have to say «yes» to add a key when connecting to a server that you’ve connected to before. You can test by just backing the file up before you delete it (just changing the name is enough).

Источник

Thread: ssh/rsync issues

Thread Tools

Display

ssh/rsync issues

So i recently updated my server from 10.04 to 12.04. I had a script that I used to backup and sync my music from my laptop to the server

rsync and openssh are installed on both machines and googling has turned up nothing so far. any ideas?
I can vnc into the box no problem

Last edited by djyoung4; October 16th, 2012 at 09:52 PM .

Re: ssh/rsync issues

Let’s try to make sure your ssh connection is working OK.

Could you post the result of an ssh connection using the triple verbose option?

Re: ssh/rsync issues

Re: ssh/rsync issues

It look like the ssh service is not running, or set to use another port.

Could you post the results of these commands on the server?

Re: ssh/rsync issues

ha seems to be my problem

Re: ssh/rsync issues

The server side of the openssh package has not been installed yet on the server.

Install it like this:

Let us know how it goes.
Regards.

Re: ssh/rsync issues

I cant seem to figure out where to add the new RSA key. Hopefully someone isn’t really doing something nasty.
edit: I added it in the file and ran the script and still no luck. just gave me some other errors and then closed the terminal before I could copy them

Last edited by djyoung4; October 16th, 2012 at 10:38 PM .

Re: ssh/rsync issues

Either remove the second line of your

/.ssh/know_hosts, or just remove the file (if you don’t ssh to other machines).

Try again, and let us know how it goes.
Regards.

Re: ssh/rsync issues

I think you’re getting that because your system is recognizing that the server has changed and now has a different key. If purge the server’s entry from

/.ssh/known_hosts you should be OK again.

If you can’t decipher which is the server’s (which is not unlikely!) I think you can just purge the whole file. The only downside side that I’ve seen is that you just have to say «yes» to add a key when connecting to a server that you’ve connected to before. You can test by just backing the file up before you delete it (just changing the name is enough).

Источник

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