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




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

------

--
Paul Klapperich

On Wed, Feb 8, 2017 at 4:36 PM, Rowland Penny via samba <
samba@xxxxxxxxxxxxxxx> wrote:

> On Wed, 8 Feb 2017 15:59:16 -0600
> Paul Klapperich via samba <samba@xxxxxxxxxxxxxxx> wrote:
>
> > I have a FreeNAS 9.3 server running Samba Version 4.3.6 and a bunch of
> > Windows and Linux clients. Everything's been running fine for a while
> > and nothing changed on the server.
> >
> > Recently (Jan 27th) some of the Archlinux clients updated from a 4.8.x
> > kernel to a 4.9.x kernel. Again, things ran fine. Then on Jan 30th
> > around 2am the Archlinux clients using 4.9.x kernels and utilizing
> > mount.cifs to access samba shares began thrashing on TCP port 445,
> > causing high CPU load on the server. These machines now cause
> > thrashing after 15-20 minutes whenever a share is mounted using
> > mount.cifs.
> >
> > When it's thrashing, I see thousands of opened ports from a single
> > client: # sockstat -4 | grep 10.0.1.87 | wc
> >    10013   70091  740962
> >
> > And on the client, the port is constant changing:
> > $ netstat -net | grep 10.0.0.8
> > tcp        0      0 10.0.1.87:53122         10.0.0.8:445
> >  ESTABLISHED 0          1253359
> > $ netstat -net | grep 10.0.0.8
> > tcp        0      0 10.0.1.87:53700         10.0.0.8:445
> >  ESTABLISHED 0          1253439
> > $ netstat -net | grep 10.0.0.8
> > tcp        0      0 10.0.1.87:53926         10.0.0.8:445
> >  ESTABLISHED 0          1254557
> > $ netstat -net | grep 10.0.0.8
> > tcp        0      0 10.0.1.87:54148         10.0.0.8:445
> >  ESTABLISHED 0          1253578
> > $ netstat -net | grep 10.0.0.8
> > tcp        0      0 10.0.1.87:54352         10.0.0.8:445
> >  ESTABLISHED 0          1253604
> > $ netstat -net | grep 10.0.0.8
> > tcp        0      0 10.0.1.87:54518         10.0.0.8:445
> >  ESTABLISHED 0          1254685
> > $ netstat -net | grep 10.0.0.8
> > tcp        0      0 10.0.1.87:54698         10.0.0.8:445
> >  ESTABLISHED 0          1252177
> >
> > As a work around, I can downgrade these client machines to any 4.8.x
> > kernel and the issue goes away. My suspicion is something is weird in
> > my smb.conf and a change in the 4.9.x kernels exposes that weirdness.
> > Or maybe there's a bug that was introduced in 4.9 and our setup
> > exposes it.
> >
> > I've built 4.10rc kernels from Linus's git repo and they also have the
> > problem. The 4.9 kernel I built from Linus's git has the problem, but
> > the 4.8 kernel I built does not, so I don't think it's related to any
> > patching done by Archlinux. I don't understand why the issue didn't
> > happen immediately after upgrading kernels on the 27th, but now it
> > very consistently acts up after less than 20 minutes.
> >
> > Attached is the smb.conf used on one of my FreeNAS servers. I was
> > able to copy that config to an Archlinux system running Samba version
> > 4.5.3 (commenting lines 24, 25, 55, and 79 and adjusting the
> > "interfaces =" line) and the problem persists, so it doesn't appear
> > to be specific to FreeNas or Samba 4.3.6.
> >
> > --
> > Paul Klapperich
>
> Unfortunately, this list removes attachments, you will need to post
> your smb.conf in the actual message.
>
> Rowland
>
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