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Re: [Samba] Need help troubleshooting TCP thrashing, possible kernel bug?




Well that was easier than I thought. Here's the default config provided by
archlinux's samba package, but with "deadtime = 1" included. With this
config, shares mounted via mount.cifs thrash on port 445 after a few
minutes. I think the reconnect logic in the kernel's CIFS client is broken.
Should I report this on the kernel mailing list?

-----
# This is the main Samba configuration file. You should read the
# smb.conf(5) manual page in order to understand the options listed
# here. Samba has a huge number of configurable options (perhaps too
# many!) most of which are not shown in this example
#
# Any line which starts with a ; (semi-colon) or a # (hash)
# is a comment and is ignored. In this example we will use a #
# for commentry and a ; for parts of the config file that you
# may wish to enable
#
# NOTE: Whenever you modify this file you should run the command "testparm"
# to check that you have not made any basic syntactic errors.
#
#======================= Global Settings
=====================================
[global]

# workgroup = NT-Domain-Name or Workgroup-Name
   workgroup = MYGROUP

# server string is the equivalent of the NT Description field
   server string = Samba Server

# This option is important for security. It allows you to restrict
# connections to machines which are on your local network. The
# following example restricts access to two C class networks and
# the "loopback" interface. For more examples of the syntax see
# the smb.conf man page
;   hosts allow = 192.168.1. 192.168.2. 127.

# if you want to automatically load your printer list rather
# than setting them up individually then you'll need this
   printcap name = /etc/printcap
   load printers = yes

# It should not be necessary to spell out the print system type unless
# yours is non-standard. Currently supported print systems include:
# bsd, sysv, plp, lprng, aix, hpux, qnx
;   printing = bsd

# Uncomment this if you want a guest account, you must add this to
/etc/passwd
# otherwise the user "nobody" is used
;  guest account = pcguest

# this tells Samba to use a separate log file for each machine
# that connects
   log file = /var/log/samba/%m.log

# Put a capping on the size of the log files (in Kb).
   max log size = 50

# Security mode. Most people will want user level security. See
# security_level.txt for details.
   security = user
# Use password server option only with security = server
;   password server = <NT-Server-Name>

# Password Level allows matching of _n_ characters of the password for
# all combinations of upper and lower case.
;  username level = 8

# You may wish to use password encryption. Please read
# ENCRYPTION.txt, Win95.txt and WinNT.txt in the Samba documentation.
# Do not enable this option unless you have read those documents
;  encrypt passwords = yes
;  smb passwd file = /etc/samba/smbpasswd

# The following are needed to allow password changing from Windows to
# update the Linux sytsem password also.
# NOTE: Use these with 'encrypt passwords' and 'smb passwd file' above.
# NOTE2: You do NOT need these to allow workstations to change only
#        the encrypted SMB passwords. They allow the Unix password
#        to be kept in sync with the SMB password.
;  unix password sync = Yes
;  passwd program = /usr/bin/passwd %u
;  passwd chat = *New*UNIX*password* %n\n *ReType*new*UNIX*password* %n\n
*passwd:*all*authentication*tokens*updated*successfully*

# Unix users can map to different SMB User names
;  username map = /etc/samba/smbusers

# Using the following line enables you to customise your configuration
# on a per machine basis. The %m gets replaced with the netbios name
# of the machine that is connecting
;   include = /etc/samba/smb.conf.%m

# Configure Samba to use multiple interfaces
# If you have multiple network interfaces then you must list them
# here. See the man page for details.
;   interfaces = 192.168.12.2/24 192.168.13.2/24

# Configure remote browse list synchronisation here
#  request announcement to, or browse list sync from:
# a specific host or from / to a whole subnet (see below)
;   remote browse sync = 192.168.3.25 192.168.5.255
# Cause this host to announce itself to local subnets here
;   remote announce = 192.168.1.255 192.168.2.44

# Browser Control Options:
# set local master to no if you don't want Samba to become a master
# browser on your network. Otherwise the normal election rules apply
;   local master = no

# OS Level determines the precedence of this server in master browser
# elections. The default value should be reasonable
;   os level = 33

# Domain Master specifies Samba to be the Domain Master Browser. This
# allows Samba to collate browse lists between subnets. Don't use this
# if you already have a Windows NT domain controller doing this job
;   domain master = yes

# Preferred Master causes Samba to force a local browser election on startup
# and gives it a slightly higher chance of winning the election
;   preferred master = yes

# Use only if you have an NT server on your network that has been
# configured at install time to be a primary domain controller.
;   domain controller = <NT-Domain-Controller-SMBName>

# Enable this if you want Samba to be a domain logon server for
# Windows95 workstations.
;   domain logons = yes

# if you enable domain logons then you may want a per-machine or
# per user logon script
# run a specific logon batch file per workstation (machine)
;   logon script = %m.bat
# run a specific logon batch file per username
;   logon script = %U.bat

# Where to store roving profiles (only for Win95 and WinNT)
#        %L substitutes for this servers netbios name, %U is username
#        You must uncomment the [Profiles] share below
;   logon path = \\%L\Profiles\%U

# All NetBIOS names must be resolved to IP Addresses
# 'Name Resolve Order' allows the named resolution mechanism to be specified
# the default order is "host lmhosts wins bcast". "host" means use the unix
# system gethostbyname() function call that will use either /etc/hosts OR
# DNS or NIS depending on the settings of /etc/host.config,
/etc/nsswitch.conf
# and the /etc/resolv.conf file. "host" therefore is system configuration
# dependant. This parameter is most often of use to prevent DNS lookups
# in order to resolve NetBIOS names to IP Addresses. Use with care!
# The example below excludes use of name resolution for machines that are
NOT
# on the local network segment
# - OR - are not deliberately to be known via lmhosts or via WINS.
; name resolve order = wins lmhosts bcast

# Windows Internet Name Serving Support Section:
# WINS Support - Tells the NMBD component of Samba to enable it's WINS
Server
;   wins support = yes

# WINS Server - Tells the NMBD components of Samba to be a WINS Client
# Note: Samba can be either a WINS Server, or a WINS Client, but NOT both
;   wins server = w.x.y.z

# WINS Proxy - Tells Samba to answer name resolution queries on
# behalf of a non WINS capable client, for this to work there must be
# at least one WINS Server on the network. The default is NO.
;   wins proxy = yes

# DNS Proxy - tells Samba whether or not to try to resolve NetBIOS names
# via DNS nslookups. The built-in default for versions 1.9.17 is yes,
# this has been changed in version 1.9.18 to no.
   dns proxy = no

# Case Preservation can be handy - system default is _no_
# NOTE: These can be set on a per share basis
;  preserve case = no
;  short preserve case = no
# Default case is normally upper case for all DOS files
;  default case = lower
# Be very careful with case sensitivity - it can break things!
;  case sensitive = no

deadtime = 1

#============================ Share Definitions
==============================
[homes]
   comment = Home Directories
   browseable = no
   writable = yes

# Un-comment the following and create the netlogon directory for Domain
Logons
; [netlogon]
;   comment = Network Logon Service
;   path = /home/netlogon
;   guest ok = yes
;   writable = no
;   share modes = no


# Un-comment the following to provide a specific roving profile share
# the default is to use the user's home directory
;[Profiles]
;    path = /home/profiles
;    browseable = no
;    guest ok = yes


# NOTE: If you have a BSD-style print system there is no need to
# specifically define each individual printer
[printers]
   comment = All Printers
   path = /var/spool/samba
   browseable = no
# Set public = yes to allow user 'guest account' to print
   guest ok = no
   writable = no
   printable = yes

# This one is useful for people to share files
;[tmp]
;   comment = Temporary file space
;   path = /tmp
;   read only = no
;   public = yes

# A publicly accessible directory, but read only, except for people in
# the "staff" group
;[public]
;   comment = Public Stuff
;   path = /home/samba
;   public = yes
;   read only = yes
;   write list = @staff

# Other examples.
#
# A private printer, usable only by fred. Spool data will be placed in
fred's
# home directory. Note that fred must have write access to the spool
directory,
# wherever it is.
;[fredsprn]
;   comment = Fred's Printer
;   valid users = fred
;   path = /homes/fred
;   printer = freds_printer
;   public = no
;   writable = no
;   printable = yes

# A private directory, usable only by fred. Note that fred requires write
# access to the directory.
;[fredsdir]
;   comment = Fred's Service
;   path = /usr/somewhere/private
;   valid users = fred
;   public = no
;   writable = yes
;   printable = no

# a service which has a different directory for each machine that connects
# this allows you to tailor configurations to incoming machines. You could
# also use the %u option to tailor it by user name.
# The %m gets replaced with the machine name that is connecting.
;[pchome]
;  comment = PC Directories
;  path = /usr/pc/%m
;  public = no
;  writable = yes

# A publicly accessible directory, read/write to all users. Note that all
files
# created in the directory by users will be owned by the default user, so
# any user with access can delete any other user's files. Obviously this
# directory must be writable by the default user. Another user could of
course
# be specified, in which case all files would be owned by that user instead.
;[public]
;   path = /usr/somewhere/else/public
;   public = yes
;   only guest = yes
;   writable = yes
;   printable = no

# The following two entries demonstrate how to share a directory so that two
# users can place files there that will be owned by the specific users. In
this
# setup, the directory should be writable by both users and should have the
# sticky bit set on it to prevent abuse. Obviously this could be extended to
# as many users as required.
;[myshare]
;   comment = Mary's and Fred's stuff
;   path = /usr/somewhere/shared
;   valid users = mary fred
;   public = no
;   writable = yes
;   printable = no
;   create mask = 0765
-----

--
Paul Klapperich

On Wed, Feb 8, 2017 at 7:56 PM, Paul Klapperich <
paul.klapperich@xxxxxxxxxxxxxxxxx> wrote:

> I think it should be neither. Ugh... FreeNAS UI doesn't let me disable the
> Domain Logons setting for some reason, so I'll have to talk to them on that
> one and it seems they have no option for me to modify the server role.
> Thankfully I can edit smb.conf directly on the archlinux box where I was
> able to duplicate the issue.
>
> Setting sever role = auto, domain logons = yes doesn't fix the TCP
> thrashing and works with the SIDs already populated in LDAP.
>
> It looks like removing "deadtime = 15" from the smb.conf prevents the TCP
> thrashing. If I set "deadtime  = 1" then the thrashing happens after 3
> minutes or so.
>
> I'll see if I can put together a conf file that isn't a disaster but still
> expresses the error.
>
> --
> Paul Klapperich
>
> On Wed, Feb 8, 2017 at 5:05 PM, Rowland Penny via samba <
> samba@xxxxxxxxxxxxxxx> wrote:
>
>> On Wed, 8 Feb 2017 16:43:53 -0600
>> Paul Klapperich via samba <samba@xxxxxxxxxxxxxxx> wrote:
>>
>> > Very well. Here is the affected smb.conf.
>> > ------
>> > [global]
>> >     server min protocol = NT1
>> >     server max protocol = SMB3
>> >     interfaces = 127.0.0.1 10.0.0.8
>> >     bind interfaces only = yes
>> >     encrypt passwords = yes
>> >     dns proxy = no
>> >     strict locking = no
>> >     oplocks = yes
>> >     deadtime = 15
>> >     max log size = 51200
>> >     max open files = 2830016
>> >     logging = file
>> >     load printers = no
>> >     printing = bsd
>> >     printcap name = /dev/null
>> >     disable spoolss = yes
>> >     getwd cache = yes
>> >     guest account = nobody
>> >     map to guest = Bad User
>> >     obey pam restrictions = yes
>> >     directory name cache size = 0
>> >     kernel change notify = no
>> >     panic action = /usr/local/libexec/samba/samba-backtrace
>> >     nsupdate command = /usr/local/bin/samba-nsupdate -g
>> >     server string = backup of files
>> >     ea support = yes
>> >     store dos attributes = yes
>> >     lm announce = yes
>> >     hostname lookups = yes
>> >     unix extensions = no
>> >     acl allow execute always = true
>> >     dos filemode = yes
>> >     multicast dns register = no
>> >     local master = no
>> >     idmap config *: backend = tdb
>> >     idmap config *: range = 10000-90000
>> >     server role = member server
>> >     security = user
>> >     passdb backend = ldapsam:ldap://ldap0.packetdigital.com
>> >     ldap admin dn = cn=admin,dc=packetdigital,dc=com
>> >     ldap suffix = dc=packetdigital,dc=com
>> >     ldap user suffix = ou=Users
>> >     ldap group suffix = ou=Groups
>> >     ldap ssl = off
>> >     ldap replication sleep = 1000
>> >     ldap passwd sync = yes
>> >     ldapsam:trusted = yes
>> >     netbios name = HAMMER
>> >     workgroup = PACKETDIGITAL
>> >     domain logons = yes
>> >     idmap config PACKETDIGITAL: backend = ldap
>> >     idmap config PACKETDIGITAL: range = 10000-90000
>> >     idmap config PACKETDIGITAL: ldap url = ldap0.packetdigital.com
>> >     pid directory = /var/run/samba
>> >     create mask = 0666
>> >     directory mask = 0777
>> >     client ntlmv2 auth = yes
>> >     dos charset = CP437
>> >     unix charset = UTF-8
>> >     log level = 1
>> >     #map unix users to 1 or more names
>> >     ## can map an @group to a username
>> >     #username map = /mnt/storage/configs/samba_users.map
>> >     follow symlinks = yes
>> >     wide links = yes
>> >     unix extensions = no
>> >     create mask = 0660
>> >     idmap uid = 10000-90000
>> >     idmap gid = 10000-90000
>> >
>> >
>> > [Software]
>> >     path = /mnt/storage/cifs-share/Software
>> >     printable = no
>> >     veto files = /.snapshot/.windows/.mac/.zfs/
>> >     writeable = yes
>> >     browseable = yes
>> >     vfs objects = zfs_space zfsacl
>> >     hide dot files = yes
>> >     guest ok = no
>> >     nfs4:mode = special
>> >     nfs4:acedup = merge
>> >     nfs4:chown = true
>> >     zfsacl:acesort = dontcare
>> >     create mask = 0775
>> >     force create mode = 0775
>> >     directory mask = 0775
>> >     force directory mode = 0775
>> >     force group = Software
>> >     valid users = @Software, @Software-RO
>> >     read only = yes
>> >     write list = @Software
>> >
>>
>> I think you need to go and read 'man smb.conf'
>>
>> 'server role = member server' means it should be joined to a windows
>> domain, but 'domain logons = yes' makes it a PDC, so which is it ?
>>
>> Rowland
>>
>> --
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>>
>
>
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