[Samba] Samba and the InterWeb
Alex Hooper
ahooper at bmjgroup.com
Wed Feb 13 10:57:31 GMT 2008
Scott Lovenberg uttered:
> Alex Hooper wrote:
>> Hi,
>>
>> We have an office-based Windows-locked publishing system whose only
>> delivery mechanism is to write to a local filesystem, and a
>> requirement for its output to be available to a collocated production
>> environment comprising Solaris and Linux boxes. The 'obvious' solution
>> was to run a Samba server on one of the collocated Linux boxes and
>> mount the share it provides on the relevant Windows machines in the
>> office. And this is what I have done. This works, but encounters the
>> problem I am about to describe.
>>
>> SCENARIO ONE:
>>
>> Connecting to the server/share in Explorer (Windows XP) by typing the
>> path (\\dns.host.name\share) into the address bar is accomplished
>> without problem, as is receiving a directory listing. But uploading a
>> file to the remote share (by drag and dropping) causes Explorer to
>> freeze for anything between 10 and 30 seconds after which the file
>> transfers at good speed.
>>
>> SCENARIO TWO:
>>
>> Map the remote share, using same connection details. Now copy is often
>> fine, but sometimes will just fail with a "Cannot copy
>> <filename>: The specified network name is no longer available." and
>> leave a zero-length file at the remote end.
>>
>> Not infrequently, smbd processes are being left in an 'uninterruptible
>> sleep' state.
>>
>> If I mount the remote share via smbmount onto a Linux server in the
>> office, I don't encounter any of these problems.
>>
>> Packet-sniffing on scenario one shows that the pause is happening
>> before any set-up for the file transfer: it looks like the client
>> disconnects, then there's a pause, then it reconnects.
>>
>> I'm using Samba version 3.0.25b-1.el4_6.4 on RHEL ES release 4.
>> Clients are Windows XP Pro. Our office has a fairly large and complex
>> LAN which is managed by a separate department. Access to the Internet
>> is, not surprisingly, via a NATting gateway. Appropriate ports have
>> been opened in the firewalls, though all communication is in
>> Direct-hosted mode (ie, I only see traffic on port 445/tcp).
>>
>> smb.conf looks like this:
>>
>> [global]
>>
>> workgroup = WG123
>> netbios name = n2323 # hostname of server
>> server string = FOO-BAR-Samba
>>
>> #wins proxy = yes
>> #wins server = xxx.xx.xx.x
>>
>> security = user
>> passdb backend = tdbsam
>>
>> load printers = no
>>
>> # idle time (mins) before client is disconnected
>> dead time = 15
>> keepalive = 10
>> socket options = IPTOS_THROUGHPUT SO_SNDBUF=8576
>> inherit permissions = yes
>>
>> [test-xml]
>> path = /stuff/test-xml
>> writeable = Yes
>> public = no
>>
>> Could anyone suggest what might be going on here?
>>
>> Thanks,
>>
>> Alex.
> On scenario1, is it (Windows client) trying to connect to port 445 on
> the server, being dropped instead of rejected, timing out, and then
> establishing a connection on port 139? I think by default Windows tries
> to connect to both at the same time or something weird like that.
>
No. There is no attempt to use port 139: only 445 is approached.
>
> On scenario2, I've seen behavior something akin to this on a corrupted
> e1000 kernel module. I've also seen bad cables (twice where gigabit and
> mii are concerned, IIRC) that behave all kinds of weird, at any given
> moment.
>
The server's using the bnx2 module and the NIC is at 100MB FD. I'm not
noting any other network weirdness, which would seem to suggest cabling
is probably OK, wouldn't it?
> Anyways, FWIW, how does your 'netstat -s' output look? Are you getting
> a considerable number of connection resets being sent or received?
>
No. All the "reset sent"s in the diff below belong to an unrelated
application. In the time between the two netstats compared below,
various stalling transfers were made and one "network name is no longer
available" was received:
# diff -Bub /root/netstat-20080213-0939 /root/netstat-20080213-1016
--- /root/netstat-20080213-0939 2008-02-13 09:39:24.000000000 +0000
+++ /root/netstat-20080213-1016 2008-02-13 10:16:34.000000000 +0000
@@ -1,43 +1,44 @@
Ip:
- 4336 total packets received
+ 21933 total packets received
0 forwarded
0 incoming packets discarded
- 4335 incoming packets delivered
- 4134 requests sent out
+ 20292 incoming packets delivered
+ 19069 requests sent out
Icmp:
- 26 ICMP messages received
+ 92 ICMP messages received
0 input ICMP message failed.
ICMP input histogram:
- echo requests: 26
- 26 ICMP messages sent
+ echo requests: 92
+ 92 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
- echo replies: 26
+ echo replies: 92
Tcp:
- 6 active connections openings
- 161 passive connection openings
+ 11 active connections openings
+ 169 passive connection openings
0 failed connection attempts
- 0 connection resets received
- 93 connections established
- 4176 segments received
- 3992 segments send out
+ 1 connection resets received
+ 97 connections established
+ 18529 segments received
+ 17417 segments send out
0 segments retransmited
0 bad segments received.
- 259 resets sent
+ 333 resets sent
Udp:
- 132 packets received
+ 1663 packets received
0 packets to unknown port received.
0 packet receive errors
- 116 packets sent
+ 1560 packets sent
TcpExt:
ArpFilter: 0
- 74 TCP sockets finished time wait in fast timer
- 18 delayed acks sent
- 3191 packets directly queued to recvmsg prequeue.
- 396 packets directly received from prequeue
- 2006 packets header predicted
- TCPPureAcks: 969
- TCPHPAcks: 1773
+ 78 TCP sockets finished time wait in fast timer
+ 880 delayed acks sent
+ 14318 packets directly queued to recvmsg prequeue.
+ 1431219 packets directly received from prequeue
+ 10014 packets header predicted
+ 1063 packets header predicted and directly queued to user
+ TCPPureAcks: 1612
+ TCPHPAcks: 10445
TCPRenoRecovery: 0
TCPSackRecovery: 0
TCPSACKReneging: 0
--
Alex Hooper | <w> www.bmjpg.com
Systems and Database Administration | <e> ahooper at bmjgroup.com
BMJ Knowledge, BMJ Publishing Group | <t> +44 20 7383 6049
BMA House, LONDON, WC1H 9JR |
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