[Samba] Need help troubleshooting TCP thrashing, possible kernel bug?
Paul Klapperich
paul.klapperich at packetdigital.com
Thu Feb 9 02:15:05 UTC 2017
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 at packetdigital.com> 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 at lists.samba.org> wrote:
>
>> On Wed, 8 Feb 2017 16:43:53 -0600
>> Paul Klapperich via samba <samba at lists.samba.org> 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
>>
>> --
>> To unsubscribe from this list go to the following URL and read the
>> instructions: https://lists.samba.org/mailman/options/samba
>>
>
>
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