Samba/FTP slow write fast read

Sun Nov 4 10:38:08 MST 2012

George,

On Sat, Nov 3, 2012 at 8:56 PM, George Toft <george at georgetoft.com> wrote:

>  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 :)
>

Also the version of SMB on the VMware host?

SMB - not SMB2, right?
Upgrade that Vmware to ESXi.

>
> 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 at 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 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).
>  --
> (503) 754-4452 Android
> (623) 239-3392 Skype
> (623) 688-3392 Google Voice
> **
> it-clowns.com
> Chief Clown
>
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-- 
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(623) 688-3392 Google Voice
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