Many notebooks including the Dell XPS 13 now have 4k displays, ever since I bought this notebook I noticed issues when I RDP’d into my servers or home laptop with the mouse behaving very wierdly.

The mouse would rapidly switch from guest to host mode when trying to control some windows VMs, at first I thought it was a vmware tools issue or possible the touchpad or touchscreen but I eventually found the solution!

You must disable display scaling on the vmware vsphere application and all the woes vanish!

I hope this helps some others, it was driving me insane! I was about to buy a new laptop!

 

-Mike

This link is a life saver for anyone who uses Veeam or migrates servers from one IP range or site to another and needs servers to work on the other end.

 

https://blog.blksthl.com/2013/03/18/fix-the-trust-relationship-between-this-workstation-and-the-primary-domain-failed/

• Posted in: Networks
• Tags:

5 Apr2006

Sometimes we need to connect two or more geographically distrubuted ethernet networks to one broadcast domain. There can be two different office networks of some company which uses smb protocol partially based on broadcast network messages. Another example of such situation is computer cafes: a couple of computer cafes can provide to users more convinient environment forr playing multiplayer computer games without dedicated servers.

Both sample networks in this article need to have one *nix server for bridging. Our networks can be connected by any possible hardware that provides IP connection between them.

Short description: In described configuration we are connecting two remote LANs to make them appearing as one network with 192.168.1.0/24 address space (however physically, presense of bridges in network configuration is not affecting IP protocol and is fully transparent for it, so you can freely select any address space). Both of the bridging servers has two network interfaces: one (as eth0 in our example) connested to the LAN, and second (eth1) is being used as transport to connect networks. When ethernet tunnel between gateways in both networks will be bringed up we will connect tunnel interfaces with appropriate LAN interfaces with bridge interfaces. Schematically this configuration can be following:

          +-------+                       +-------+
          |  br0  |                       |  br0  |
          +-------+                       +-------+
           |     |                         |     |
Network 1  |     |                         |     |   Network 2
----------eth0  tap0---eth1........eth1---tap0  eth0---------------

Setting Up Bridging Servers

Notice: This article describes Debian GNU/Linux servers setup. If you are using another distribution, there can be some differences in network configuration and package management, but the main idea of described actions will be the same.

First of all, we need to check if tun and bridge modules is not included in current kernel. If they are not includen, we need to rebuild kernel with CONFIG_TUN and CONFIG_BRIDGE options.

Next, we need to create tunnel device file for our tunnel:

    # cd /dev
    # ./MAKEDEV tun
    # mkdir misc
    # ln -s /dev/net /dev/misc/net

Notice: Last command is needed to make vtun work, because authors build for debian is looking for tunnel device driver at /dev/misc/net/tun.

To create ethernet tunnel between bridging servers we will use vtun software. Debian package (and also source code and other OS packages) can be loaded from authors site.

When package file vtun_X.Y-Z_i386.deb will be downloaded, we will need to install all required packages:

    # apt-get install bridge-utils ebtables iptables libssl0.9.6
    ...
    # dpkg -i vtun_X.Y-Z_i386.deb

When vtun will be installed, we will need to select one of the bridging servers as master and second server will be slave and appropriately change vtund-start.conf and vtund.conf file in /etc/ on buth servers. Complete config files for master is following.

/etc/vtund-start.conf

----cut-here------------------------------------
--server-- 5000
----cut-here------------------------------------

/etc/vtund.conf

----cut-here------------------------------------
options {                                                                                      
    port 5000;            # Listen on this port.

    # Syslog facility
    syslog        daemon;

    # Path to various programs
    ifconfig      /sbin/ifconfig;
    route         /sbin/route;
    firewall      /sbin/iptables;
    ip            /sbin/ip;
}

default {
    compress no;
    encrypt no;
    speed 0;
}

rembridge {
    passwd Pa$$Wd;
    type ether;
    proto udp;
    keepalive yes;
    compress no;
    encrypt yes;
    
    up {
	# Connection is Up 
	ifconfig "%% up";
	program "brctl addif br0 %%";
    };
    
    down {
	# Connection is Down 
	ifconfig "%% down";
    };
}
----cut-here------------------------------------

Slave server config files is following:

/etc/vtund-start.conf

----cut-here------------------------------------
rembridge 10.1.1.1 -p
----cut-here------------------------------------

Notice: In this example 10.1.1.1 is transport address of master server.

/etc/vtund.conf

----cut-here------------------------------------
options {
  # Path to various programs
  ifconfig	/sbin/ifconfig;
  route		/sbin/route;
  firewall	/sbin/iptables;
}

korsar {
  pass  Pa$$Wd;		# Password
  type  ether;		# Ethernet tunnel
  up {
	# Connection is Up 
	ifconfig "%% up";
	program "brctl addif br0 %%"
  };
  down {
	# Connection is Down 
	ifconfig "%% down";
  };
}
----cut-here------------------------------------

To bring up bridge between LAN ethernet interface and our newly created tunnel interface we need to create bridge interface. To complete this task we will add br0 interface description to /etc/network/interfaces file:

auto br0
iface br0 inet static
    address 192.168.1.199
    netmask 255.255.255.0
    bridge_ports eth0

Notice: IP-addresses on both sides of our bridge must be unique in both networks. eth0 is LAN interface.

Now, we need to bring this interface up:

    # ifup br0

When br0 interface will be created, we will be able to start vtun.

    # /etc/init.d/vtund restart

If everything was done correctly, we will see following results on both sersers (br0 and tap0 interfaces):

    # ifconfig tap0
    tap0  Link encap:Ethernet  HWaddr 00:FF:B2:91:CA:DE
	  UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
	  RX packets:701818 errors:0 dropped:0 overruns:0 frame:0
	  TX packets:405939 errors:0 dropped:0 overruns:0 carrier:0
	  collisions:0 txqueuelen:1000 
	  RX bytes:975889241 (930.6 MiB)  TX bytes:44704104 (42.6 MiB)

    # ifconfig br0
    br0   Link encap:Ethernet  HWaddr 00:02:44:2A:03:30  
          inet addr:192.168.1.199  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:2660 errors:0 dropped:0 overruns:0 frame:0
          TX packets:42 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:239368 (233.7 KiB)  TX bytes:2338 (2.2 KiB)

    #

If we need to see current state of bridge interface, we can use brctl tool:

    # brctl show br0
    bridge name     bridge id               STP enabled     interfaces
    br0             8000.0002442a0330       no              eth0
	                                                    tap0
    #

When all of described steps will be completed, our computers in both networks will be able to communicate with each other. IP addresses on bridge interfaces can be used for troubleshooting network connection. And last, if you need, you can turn on compression or enrtyption of data within created tunnel.

Ever been in a situation where you have a remotely hosed virtual machine and you want to clone it to your local vCenter cluster?

 

Just about all V2V migrations are cold migrations, which require that the source system be powered off during the conversion process. It is, however, possible to perform a hot migration of a virtual machine using the hot migration method as described in How to Import a Virtual Machine into ESXi: Part 1. After installing vCenter Converter Standalone to the virtual machine, launch the Conversion wizard. Select “Powered-On Machine” from the drop-down menu, click “Local Machine,” and then follow the same steps as described in the section P2V: Hot Migration.

 

V2V: Hot Migration

 

Suggestion: stop all services on the source VM if there are any database servers or services which would be changing data during the process.

1. To perform a V2V hot migration in vCenter Converter Standalone, click “Convert Machine.” Select “Powered-on Machine” from the drop-down menu on the Source System tab.
2. Select “This Local Machine” if you intend to migrate the physical machine to where VMware vCenter Conversion is installed. Otherwise, click “A Remote Machine” and then enter the IP address and login credentials for the source system. Click “Next.”
3. Select “VMware Infrastructure Virtual Machine” from the drop-down menu. Enter the server address and login credentials for the system running VMware ESX/ESXi. Click “Next.”
4. Review the system parameters on the Options tab. To make changes to a device, network or service option, select the desired setting from the list.

Click “Advanced Options” to synchronize the source system with the destination system immediately after cloning or at a scheduled date and time. If you’re cloning a Windows machine, it’s recommended that you check “Install VMware Tools on the Destination Virtual Machine” and “Remove System Restore Checkpoints on Destination” on the Post-Conversion tab.

Click “Next” after making the desired modifications, if applicable.

5. Review your configuration on the Summary tab; then click “Finish” to perform the migration.

 

Hard to find this info, so I figured I would help everyone out!

 

With the configuration & error stating that it can see the slave controller and not the primary controller what you can do is to swap the controllers and put the slave(right side of the unit if looking at the MD3000i from the back) with the primary controller and try to see if the system will come up with just the primary controller (was slave controller). If the MD3000i comes up with the primary controller in then add in the secondary controller and check the serial output to ensure that it comes up.

Now if you wanted to just try & reset the array here is the way you would do that.

1. Startup a terminal emulation program like putty, teraterm, minicom or hyperterminal using these terminal settings (115200-8-n-1).

2. Send a from the terminal shell. This is accomplished by <Ctrl><PAUSE/BREAK> within HyperTerminal or Putty, use <Ctrl><A><F> from within Minicom on Linux systems.

3. When prompted for input within 5 seconds, press <S> for the service interface menu. Also the S needs to be caps otherwise will not work

4. The user will then be prompted for a password. The Password is: supportDell

5. The menu options available are.

1) Display IP Configuration

2) Change IP Configuration

3) Reset Storage Array (SYMbol) Password

Q) Quit Menu

using arp to find out the IP of a foreign network device!

Install Wireshark on the laptop, and ensure it’s monitoring the Ethernet adapter.

set the ethernet card temporarily on your laptop at 192.168.1.2/16

Plug directly into the ethernet jack on your laptop, the device’s mgmt port. if you don’t get a link light then use a mdi-x cable or plug both units into a hub.

Keep an eye open for the DHCP Discover on the wireshark output with the brand name of the device you just bought. If not DHCP Discover then it’s statically configured and should give some pointers as to the IP address it’s using.

NOTE: If you know the MAC of the device (most have stickers) watch for the device on wireshark via the mac address using “eth.addr == xx:xx:xx:xx:xx:xx”

Hope this helps, it helped me!

 

feel free to ask any questions.

Let’s do a quick comparison.

 

Category	BlackBerry Priv	Note 5
OS	Android 5.1.1	Android 5.1.1
CPU/GPU	Qualcomm Snapdragon 808 hexa-core Adreno 418 GPU	Samsung Exynos 7420 octa-core Mali-T760MP8 GPU
Display	5.43-inch curved AMOLED 2560×1440 (540 ppi)	5.7-inch SuperAMOLED 2560×1440 (518 ppi) Corning Gorilla Glass 4
Battery	3410 mAh	3000 mAh
Removable battery	No	No
Charging	Quick Charge 2.0	Adaptive Fast Charging
Wireless charging	Qi (some models)	Qi and Powermat
Fingerprint sensor	No	Yes
Rear camera	18MP, f/2.2 OIS, phase-detect autofocus, 4K video	16MP, f/1.9 OIS, phase-detect autofocus, LED flash, 1.12 µm pixel size, 4K video
Front camera	2MP, f/2.8 1.75µm pixels	5MP wide angle lens
Storage	32GB	32 or 64GB
SD card	Yes	No
RAM	3GB	4GB
Size	147 x 77.2 x 9.4 mm 184 x 77.2 x 9.4 mm (keyboard open)	153.2 x 76.1 x 7.6 mm
Weight	192 g	171 g

 

After Many issues with my Galaxy 3,  S4, then Note4, that required me to sell them off… I conclude that the PRIV is worth a try, and for long emails it will prevail every time…

 

Mike

 

Many of you have likely had the same issue as I ran into, you have a remote server  in a remote datacenter with only DRAC6 access and no way to access the RAID card without a reboot. Well, those days are gone! I have discovered  the path to get into the RAID card and do pretty much any function you could do from the BIOS gui and more.

First,  you need to get the software installed, there’s this awesome article I found for that.

http://de.community.dell.com/techcenter/support-services/w/wiki/909.how-to-install-megacli-on-esxi-5-x

This includes the commands to view the log which is important… but doesn’t help you do much.

View system logs:

Switch with cd /opt/lsi/MegaCLI/ to the MegaCLI Folder and use this command to get your controllerlog:

./MegaCli -FwTermLog -Dsply –aALL

To Merge it in A .txt File use this:

./MegaCli -FwTermLog -Dsply –aALL > lsi.txt

The Logfile is now located in /opt/lsi/MegaCLI/

Here’s the  list of other commands I have compiled from  all over the net:

View information about the RAID adapter

For checking the firmware version, battery back-up unit presence, installed cache memory and the capabilities of the adapter:

# MegaCli -AdpAllInfo -aAll

View information about the battery backup-up unit state

# MegaCli -AdpBbuCmd -aAll

View information about virtual disks

Useful for checking RAID level, stripe size, cache policy and RAID state:

# MegaCli -LDInfo -Lall -aALL

View information about physical drives

# MegaCli -PDList -aALL

Patrol read

Patrol read is a feature which tries to discover disk error before it is too late and data is lost. By default it is done automatically (with a delay of 168 hours between different patrol reads) and will take up to 30% of IO resources.

To see information about the patrol read state and the delay between patrol read runs:
# MegaCli -AdpPR -Info -aALL

To find out the current patrol read rate, execute
# MegaCli -AdpGetProp PatrolReadRate -aALL

To reduce patrol read resource usage to 2% in order to minimize the performance impact:
# MegaCli -AdpSetProp PatrolReadRate 2 -aALL

To disable automatic patrol read:
# MegaCli -AdpPR -Dsbl -aALL

To start a manual patrol read scan:
# MegaCli -AdpPR -Start -aALL

To stop a patrol read scan:
# MegaCli -AdpPR -Stop -aALL

You could use the above commands to run patrol read in off-peak times.

Migrate from one RAID level to another

In this example, I migrate the virtual disk 0 from RAID level 6 to RAID 5, so that the disk space of one additional disk becomes available. The second command is used to make Linux detect the new size of the RAID disk.

# /usr/local/sbin/MegaCli -LDRecon -Start -r5 -L0 -a0
# echo 1 > /sys/block/sda/device/rescan

Extending an existing RAID array with a new disk

./MegaCli -LDRecon -Start -r5 -Add -PhysDrv[32:3] -L0 -a0

Create a new RAID 5 virtual disk from a set of new hard drives

First we need to now the enclosure and slot number of the hard drives we want to use for the new RAID disk. You can find them out by the first command. Then I add a virtual disk using RAID level 5, followed by the list of drives I want to use, specified by enclosure:slot syntax.

# MegaCli -PDList -aALL | egrep ‘Adapter|Enclosure|Slot|Inquiry’
# MegaCli -CfgLdAdd -r5′[252:5,252:6,252:7]’ -a0

Extending an existing RAID array with a new disk

First check the enclosure device ID and the slot number of the newly added disk with the command above. Then we reconstruct the logical drive, adding the new drive. For a RAID 5 array this command is used:

# MegaCli -LDRecon -Start -r5 -Add -PhysDrv[32:3] -L0 -a0

View reconstruction progress

When reconstructing a RAID array, you can check its progress with this command.
# MegaCli -LDRecon ShowProg L0 -a0

(replace L0 by L1 for the second virtual disk, and so on)

Configure write-cache to be disabled when battery is broken

# MegaCli -LDSetProp NoCachedBadBBU -LALL -aALL

Change physical disk cache policy

If your system is not connected to a UPS, you should disable the physical disk cache in order to prevent data loss.

# MegaCli -LDGetProp -DskCache -LAll -aALL

To enable it (only do this if you have a UPS and redundant power supplies):

# MegaCli -LDGetProp -DskCache -LAll -aALL

 

General Parameters

• Adapter parameter -aN

The parameter -aN (where N is a number starting with zero or the string ALL) specifies the adapter ID. If you have only one controller it’s safe to use ALL instead of a specific ID, but you’re encouraged to use the ID for everything that makes changes to your RAID configuration.

• Physical drive parameter      -PhysDrv [E:S]

For commands that operate on one or more pysical drives, the -PhysDrv [E:S] parameter is used, where E is the enclosure device ID in which the drive resides and S the slot number (starting with zero). You can get the enclosure device ID using MegaCli -EncInfo -aALL. The E:S syntax is also used for specifying the physical drives when creating a new RAID virtual drive (see 5).

• Virtual drive parameter -Lx

The parameter -Lx is used for specifying the virtual drive (where x is a number starting with zero or the string all).

Running the executable can be accomplished by:

shell> /opt/MegaRAID/MegaCli/MegaCli <cmd>

or

shell> cd /opt/MegaRAID/MegaCli

shell> ./MegaCli <cmd>

Gather information

• Controller information

     MegaCli -AdpAllInfo -aALL

     MegaCli -CfgDsply -aALL

     MegaCli -adpeventlog -getevents -f lsi-events.log -a0 -nolog

• Enclosure information

     MegaCli -EncInfo -aALL

• Virtual drive information

     MegaCli -LDInfo -Lall -aALL

• Physical drive information

     MegaCli -PDList -aALL

     MegaCli -PDInfo -PhysDrv [E:S] -aALL

• Battery backup information      (Cisco MSPs do not have the battery backup unit installed, but in case yours has one)

     MegaCli -AdpBbuCmd -aALL 

• Check Battery backup warning on boot.  If this is enabled on an MSP, it will require manual intervention every time the system boots

     MegaCli -AdpGetProp BatWarnDsbl -a0 

Controller management

• Silence active alarm

     MegaCli -AdpSetProp AlarmSilence -aALL

• Disable alarm

     MegaCli -AdpSetProp AlarmDsbl -aALL

• Enable alarm

     MegaCli -AdpSetProp AlarmEnbl -aALL

• Disable battery backup warning on system boot

     MegaCli -AdpSetProp BatWarnDsbl -a0

• Change the adapter rebuild rate to 60%:

MegaCli -AdpSetProp {RebuildRate -60} -aALL

Virtual drive management

• Create RAID 0, 1, 5 drive

     MegaCli -CfgLdAdd -r(0|1|5) [E:S, E:S, ...] -aN

• Create RAID 10 drive

     MegaCli -CfgSpanAdd -r10 -Array0[E:S,E:S] -Array1[E:S,E:S] -aN

• Remove drive

     MegaCli -CfgLdDel -Lx -aN

Physical drive management

• Set state to offline

     MegaCli -PDOffline -PhysDrv [E:S] -aN

• Set state to online

     MegaCli -PDOnline -PhysDrv [E:S] -aN

• Mark as missing

     MegaCli -PDMarkMissing -PhysDrv [E:S] -aN

• Prepare for removal

     MegaCli -PdPrpRmv -PhysDrv [E:S] -aN

• Replace missing drive

     MegaCli -PdReplaceMissing -PhysDrv [E:S] -ArrayN -rowN -aN

The number N of the array parameter is the Span Reference you get using MegaCli -CfgDsply -aALL and the number N of the row parameter is the Physical Disk in that span or array starting with zero (it’s not the physical disk’s slot!).

• Rebuild drive – Drive status should be “Firmware state: Rebuild”

     MegaCli -PDRbld -Start -PhysDrv [E:S] -aN

     MegaCli -PDRbld -Stop -PhysDrv [E:S] -aN

     MegaCli -PDRbld -ShowProg -PhysDrv [E:S] -aN     
     MegaCli -PDRbld -ProgDsply -physdrv [E:S] -aN

• Clear drive

     MegaCli -PDClear -Start -PhysDrv [E:S] -aN

     MegaCli -PDClear -Stop -PhysDrv [E:S] -aN

     MegaCli -PDClear -ShowProg -PhysDrv [E:S] -aN

• Bad to good

     MegaCli -PDMakeGood -PhysDrv[E:S] -aN

Changes drive in state Unconfigured-Bad to Unconfigured-Good.

Hot spare management

• Set global hot spare

     MegaCli -PDHSP -Set -PhysDrv [E:S] -aN

• Remove hot spare

     MegaCli -PDHSP -Rmv -PhysDrv [E:S] -aN

• Set dedicated hot spare

     MegaCli -PDHSP -Set -Dedicated -ArrayN,M,... -PhysDrv [E:S] -aN

Walkthrough: Rebuild a Drive that is marked ‘Foreign’ when Inserted:

• Bad to good

    MegaCli -PDMakeGood -PhysDrv [E:S]  -aALL

• Clear the foreign setting

     MegaCli -CfgForeign -Clear -aALL

• Set global hot spare

     MegaCli -PDHSP -Set -PhysDrv [E:S] -aN

Walkthrough: Change/replace a drive

1. Set the drive offline, if it is not already offline due to an error

     MegaCli -PDOffline -PhysDrv [E:S] -aN

2. Mark the drive as missing

     MegaCli -PDMarkMissing -PhysDrv [E:S] -aN

3. Prepare drive for removal

     MegaCli -PDPrpRmv -PhysDrv [E:S] -aN

4. Change/replace the drive

5. If you’re using hot spares then the replaced drive should become your new hot spare drive

     MegaCli -PDHSP -Set -PhysDrv [E:S] -aN

6. In case you’re not working with hot spares, you must re-add the new drive to your RAID virtual drive and start the rebuilding

     MegaCli -PdReplaceMissing -PhysDrv [E:S] -ArrayN -rowN -aN

     MegaCli -PDRbld -Start -PhysDrv [E:S] -aN

Gathering Standard logs

On every instance of a hard drive problem with an MSP server, we need to run the following commands to have any information about the problem:

   shell> rm –f MegaSAS.log

   shell> /opt/MegaRAID/MegaCli/MegaCli -adpallinfo -a0

   shell> /opt/MegaRAID/MegaCli/MegaCli -encinfo -a0

   shell> /opt/MegaRAID/MegaCli/MegaCli -ldinfo -lall -a0

   shell> /opt/MegaRAID/MegaCli/MegaCli -pdlist -a0

   shell> /opt/MegaRAID/MegaCli/MegaCli -adpeventlog -getevents -f lsi-events.log -a0 -nolog

   shell> /opt/MegaRAID/MegaCli/MegaCli -fwtermlog -dsply -a0 -nolog > lsi-fwterm.log

Collect the MegaSAS.log, lsi-events.log, and the lsi-fwterm.log files from the directory where the commands are run (they can be run from any directory on the MSP server) and attach the logs to the service request. You may use a program such as WinSCP (freeware) to pull the files off of the server.

 

I hope this info is useful to you all in one place, it took me a day to figure it all  out.

 

Mike

When HA cluster is first created the VMs are configured with cluster default settings concerning the VM restart priority, host isolation response, and VM monitoring. But it can be changed, and you can specify specific behavior for each virtual machine. You can for example change this settings for some high priority VMs, like your domain controller VMs etc, which needs to be started before anything else.

Introduction

Rsync, which stands for “remote sync”, is a remote and local file synchronization tool. It uses an algorithm that minimizes the amount of data copied by only moving the portions of files that have changed.

In this guide, we will cover the basic usage of this powerful utility. We will be using an Ubuntu 12.04 VPS in the examples, but you can use any modern Linux distribution to follow along.

What Is Rsync?

Rsync is a very flexible network-enabled syncing tool. It can also refer to the network protocol developed to utilize this tool.

When we reference rsync in this guide, we are mainly referring to the utility, and not the protocol.

Due to its ubiquity on Linux and Unix-like systems and its popularity as a tool for system scripts, it is included on most Linux distributions by default.

Basic Syntax

The basic syntax of rsync is very straight forward, and operates in a way that is similar to ssh, scp, and cp.

We will create two test directories and some test files with the following commands:

cd ~
mkdir dir1
mkdir dir2
touch dir1/file{1..100}

We now have a directory called dir1 with 100 empty files in it.

ls dir1

file1    file18  file27  file36  file45  file54  file63  file72  file81  file90
file10   file19  file28  file37  file46  file55  file64  file73  file82  file91
file100  file2   file29  file38  file47  file56  file65  file74  file83  file92
file11   file20  file3   file39  file48  file57  file66  file75  file84  file93
file12   file21  file30  file4   file49  file58  file67  file76  file85  file94
file13   file22  file31  file40  file5   file59  file68  file77  file86  file95
file14   file23  file32  file41  file50  file6   file69  file78  file87  file96
file15   file24  file33  file42  file51  file60  file7   file79  file88  file97
file16   file25  file34  file43  file52  file61  file70  file8   file89  file98
file17   file26  file35  file44  file53  file62  file71  file80  file9   file99

We also have an empty directory called dir2.

To sync the contents of dir1 to dir2 on the same system, type:

rsync -r dir1/ dir2

The -r option means recursive, which is necessary for directory syncing.

We could also use the -a flag instead:

rsync -a dir1/ dir2

The -a option is a combination flag.

It stands for “archive” and syncs recursively and preserves symbolic links, special and device files, modification times, group, owner, and permissions.

It is more commonly used than -r and is usually what you want to use.

An Important Note

You may have noticed that there is a trailing slash (/) at the end of the first argument in the above commands:

rsync -a dir1/ dir2

This is necessary to mean “the contents of dir1“.

The alternative, without the trailing slash, would place dir1, including the directory, within dir2. This would create a hierarchy that looks like:

~/dir2/dir1/[files]

Always double-check your arguments before executing an rsync command.

Rsync provides a method for doing this by passing the -n or –dry-run options. The -v flag (for verbose) is also necessary to get the appropriate output:

rsync -anv dir1/ dir2

sending incremental file list
./
file1
file10
file100
file11
file12
file13
file14
file15
file16
file17
file18
. . .

Compare this output to the output we get when we remove the trailing slash:

rsync -anv dir1 dir2

sending incremental file list
dir1/
dir1/file1
dir1/file10
dir1/file100
dir1/file11
dir1/file12
dir1/file13
dir1/file14
dir1/file15
dir1/file16
dir1/file17
dir1/file18
. . .

You can see here that the directory itself is transfered.

How To Use Rsync to Sync with a Remote System

Syncing to a remote system is trivial if you have SSH access to the remote machine and rsync installed on both sides. If you need to set up SSH keys, click here.

Once you have SSH access verified on between the two machines, you can sync the dir1 folder from earlier to a remote computer by using this syntax (note that we want to transfer the actual directory in this case, so we omit the trailing slash):

rsync -a ~/dir1 username@remote_host:destination_directory

This is called a “push” operation because it pushes a directory from the local system to a remote system.

The opposite operation is “pull”. It is used to sync a remote directory to the local system. If the dir1 were on the remote system instead of our local system, the syntax would be:

rsync -a username@remote_host:/home/username/dir1 place_to_sync_on_local_machine

Like “cp” and similar tools, the source is always the first argument, and the destination is always the second.

Useful Options for Rsync

Rsync provides many options for altering the default behavior of the utility. We have already discussed some of the more necessary flags.

If you are transferring files that have not already been compressed, like text files, you can reduce the network transfer by adding compression with the -z option:

rsync -az source destination

The -P flag is very helpful. It combines the flags –progress and –partial. The first of these gives you a progress bar for the transfers and the second allows you to resume interrupted transfers:

rsync -azP source destination

sending incremental file list
./
file1
           0 100%    0.00kB/s    0:00:00 (xfer#1, to-check=99/101)
file10
           0 100%    0.00kB/s    0:00:00 (xfer#2, to-check=98/101)
file100
           0 100%    0.00kB/s    0:00:00 (xfer#3, to-check=97/101)
file11
           0 100%    0.00kB/s    0:00:00 (xfer#4, to-check=96/101)
. . .

If we run the command again, we will get a shorter output, because no changes have been made.

This illustrates rsync’s ability to use modification times to determine if changes have been made.

rsync -azP source destination

sending incremental file list

sent 818 bytes received 12 bytes 1660.00 bytes/sec
total size is 0 speedup is 0.00

We can update the modification time on some of the files and see that rsync intelligently re-copies only the changed files:

touch dir1/file{1..10}
rsync -azP source destination

sending incremental file list
file1
           0 100%    0.00kB/s    0:00:00 (xfer#1, to-check=99/101)
file10
           0 100%    0.00kB/s    0:00:00 (xfer#2, to-check=98/101)
file2
           0 100%    0.00kB/s    0:00:00 (xfer#3, to-check=87/101)
file3
           0 100%    0.00kB/s    0:00:00 (xfer#4, to-check=76/101)
. . .

In order to keep two directories truly in sync, it is necessary to delete files from the destination directory if they are removed from the source. By default, rsync does not delete anything from the destination directory.

We can change this behavior with the –delete option. Before using this option, use the –dry-run option and do testing to prevent data loss:

rsync -a --delete source destination

If you wish to exclude certain files or directories located inside a directory you are syncing, you can do so by specifying them in a comma-separated list following the –exclude= option:

rsync -a --exclude=pattern_to_exclude source destination

If we have specified a pattern to exclude, we can override that exclusion for files that match a different pattern by using the –include= option.

rsync -a --exclude=pattern_to_exclude --include=pattern_to_include source destination