Re: Samba/FTP slow write fast read

>     Here are the cases I had:
>     Win7 client 1 (VMware host) using Windows Explorer, read fast,
>     write slow
>     Win7 client 1 using FTP, read fast, write slow
>     Win7 samba client 2 using Windows Explorer, read fast, write fast
>     Linux client 1 using FTP, read fast, write fast
>     Linux client 1 using smbclient, read fast, write fast

>     As you can see, anything that had to do with writes from Win7
>     client 1, which was the VMware host, went slow.

>     And this did have a large virtual drive - it was 500GB. That was
>     probably the problem :)

>     I've since moved the client from VMware to proxmox-ve on a
>     difference system and life is good.  I won't be able to pursue
>     this any further.  Same config files and it works very well.

>     Regards,

>     George Toft

>     On 11/3/2012 8:16 PM, Lisa Kachold wrote:
>>     Hi George,

>>     On Sat, Oct 27, 2012 at 6:01 PM, George Toft
>>     <george@georgetoft.com <mailto:george@georgetoft.com>> wrote:

>>         Spent several hours researching this one - can't find a
>>         solution.  I hope someone here can hit me with a clue-by-four.

>>         CentOS 6.3 64-bit virtual running under VMware 2.0.2 fresh
>>         install with FTP/Samba/NFS running.  I copied 500+GB of data
>>         from the old computer to the new one using NFS at full
>>         network speed (11+ MB/sec).  Life's good.

>>         Now here it is a day later, and my samba write speed is a
>>         blazing 80KB/sec (up from 40KB/s when I started
>>         troubleshooting).  I read samba should approach FTP speed and
>>         I verified it does - FTP writes to the new machine at about
>>         the same speed.  Reads still take place a full speed (now
>>         it's on a 1Gbps network) - 33MB/sec.  Writes . . . 99.8%
>>         slower.  I did not have this problem on the previous samba
>>         server (CentOS 4.8 32-bit).

>>         I added memory (it now has 1GB RAM, 1 GB swap) and it has 2
>>         CPU's. This had no effect.

>>         In summary, NFS works at full speed both ways.  Samba/FTP are
>>         fast on reads but snail slow on writes.

>>         My next thought is to install ClearOS, test it, and copy
>>         their smb.conf.  Or install CentOS 5.x and see if it has the
>>         same problems.

>>         Any ideas where to look on this one?  smb.conf necessary.

>>         -- 
>>         Regards,

>>         George Toft

>>     Microsoft 7 uses smb 2.2, btw --> protocol step down might add to
>>     the lag?
>>     What is your smb version on each node? CIFS clients?

>>     http://www.codefx.com/CIFS_Explained.htm

>>     A given client and server may implement different sets of
>>     protocol variations which they negotiate before starting a session.

>>     There are a great many considerations for this problem:

>>     0) Samba in VMware:
>>     http://www.vmware.com/support/ws45/doc/network_samba_ws.html

>>     1) Active .vs Passive FTP:
>>     http://www.youtube.com/watch?v=bqrlBicM8lE

>>     2) Disk type:

>>     Dynamically allocated VMware virtual disks are extremely slow
>>     with writes.  Huge virual disks over say 300 gb are also really
>>     really slow for writes.
>>     Raid 5 or greater on VVware is also extremely slow with writes,
>>     depending on the version of VMware.

>>     3) What kind of network are you using?

>>     By default there are three virtual networks created on a VMware
>>     server. They are: VMnet0 -- Bridged VMnet1 -- Host-only VMnet8 -- NAT

>>     4) Networking UDP packets for SMB:

>>     SMB uses UDP which is a connection-less protocol. In other words
>>     it simply broadcasts.

>>     UDP uses a simple communication model without implicit
>>     transmission checks for guaranteeing reliability, sequencing, or
>>     datagram integrity. Though these factors might seem to suggest
>>     that UDP is not a useful protocol, it is still widely used in
>>     particular areas where speed, more than reliability, is of utmost
>>     importance. With UDP, error checks and corrections are carried
>>     out in the communicating application, not at the network layer.
>>     However, if error checks and corrections are needed at the
>>     network layer, the application can use Transmission Control
>>     Protocol (TCP) or Stream Control Transmission Protocol (SCTP),
>>     which are specifically formulated for this reason.  Since UDP
>>     does not have the overhead of checking whether the data has
>>     reached the destination every time it is sent, it makes the
>>     protocol that much faster and more efficient. UDP is often used
>>     for time sensitive applications where missing data is preferred
>>     to late arriving data.

>>     UDP packets can also create broadcast storms (NFS 3), therefore
>>     it's not suggested that SMB or  older NFS3

>>     5) Putting it all together: Using Samba for File Sharing on a
>>     Host-only Network

>>     On a Linux host computer, VMware ESX Server can automatically
>>     install and configure a Samba server to act as a file server for
>>     Microsoft Windows guest operating systems. You can then use
>>     Windows Explorer in the virtual machine to move and copy files
>>     between virtual machine and host --- or between virtual machines
>>     on the same network --- just as you would with files on physical
>>     computers that share a network connection.

>>     The lightly modified Samba server installed by VMware ESX Server
>>     runs over the VMware ESX Server virtual Ethernet and the Samba
>>     traffic between different operating systems is isolated from
>>     actual local area networks. The source code diffs for the
>>     changes, based on Samba 2.0.6, are available from VMware.

>>         Adding User Names and Passwords to the VMware ESX Server
>>         Samba Password File

>>     You may add user names and passwords to the VMware ESX Server
>>     Samba password file at any time from a terminal window on your
>>     Linux host computer.

>>      1. Log in to the root account by typing the following command at
>>         the prompt:
>>         su
>>      2. Run the VMware ESX Server Samba password command.
>>         vmware-smbpasswd vmnet1 -a <username>

>>         where <username> is the user name you want to add.

>>      3. Follow the instructions on the screen.

>>         *Note:* vmware-smbpasswd is based on the standard Samba
>>         password program. If you are familiar with the options used
>>         in smbpasswd, you may use any of them in vmware-smbpasswd.

>>      4. Log out of the root account.
>>         exit

>>         If you receive an error message that says Unknown virtual
>>         interface "vmnet1", this indicates your machine is not using
>>         the VMware ESX Server Samba server. If your installation of
>>         VMware ESX Server does not include the VMware ESX Server
>>         Samba server and you want to set it up, log in to the root
>>         account on your host computer, then run vmware-config.pl
>>         <http://vmware-config.pl> from a terminal window on the host.
>>         When the configuration script asks Do you want this script to
>>         automatically configure your system to allow your virtual
>>         machines to access the host file system?, answer Yes.

>>         If You Are Already Running Samba

>>     If you already have Samba configured on your Linux host, the
>>     recommended approach is to modify that configuration so it
>>     includes the IP subnet used by the VMware ESX Server virtual
>>     Ethernet adapter, VMnet1. In this case, you should *not* install
>>     the VMware ESX Server Samba server when you are installing VMware
>>     ESX Server on your host. When the configuration script prompts
>>     you Do you want this script to automatically configure your
>>     system to allow your virtual machines to access the host file
>>     system?, answer No.

>>     To determine what subnet is being used by VMnet1, run
>>     /sbin/ifconfig vmnet1.

>>     It may also be possible to run both your existing Samba server
>>     and the VMware ESX Server Samba server at the same time. In order
>>     to do this, your current Samba server must be version 2.0.6 or
>>     higher and must be configured correctly.

>>     To determine the version of your Samba server, run

>>     smbd -V

>>     Tool for evaluation: http://visualsniffer.software.informer.com/
>>     References:
>>     http://chrissanders.org/2011/11/packet-carving-with-smb-and-smb2/

>>     It's  probably going to be best for you to upgrade to ESXi 5
>>     (requires specific hardware - see the compatibility list at VMware).
>>     -- 
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