CIFS (SMB、Samba)を快適に使いたい

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　linux上で、cifsとVPNを使って自分のファイルサーバにアクセスしているのですが、以下のような不満点があり、どうしたらいいか考えてみた結果、いくつか興味深いオプジョンが見つかったので、それを記録しておくだけです。ちなみに、完全な解決とまでは行ってないですが、多少改善が見られた程度って感じです。

大きなファイルをやり取りすると、同時に他のファイル操作をしたときにもっさりする
なにかと、特にvpn環境だと理由不明のファイルマネージャ等のプチフリが多発する

ちょっとしたまとめ

sudo mount -t cifs -o user=username,password="password",gid=1000,uid=1000,vers=3.11,multichannel,max_channels=16,compress //192.168.xxx.xxx/shareName /Path/To/Mount/Point

特に気になったオプション

vers=3.11

　smbプロトコルのバージョンを指定する項目で、以下のバージョンが選べる模様です。新しいほどいろんな機能が使えるようです。今回の場合は、使いたい機能が、3.11にあるので、それを指定している前提で、その他気になったオプションをリストアップします。

     vers=arg
              SMB protocol version. Allowed values are:

              • 1.0 - The classic CIFS/SMBv1 protocol.

              • 2.0 - The SMBv2.002 protocol. This was initially introduced in  Windows
                Vista  Service  Pack  1, and Windows Server 2008. Note that the initial
                release version of Windows Vista spoke  a  slightly  different  dialect
                (2.000) that is not supported.

              • 2.1  -  The SMBv2.1 protocol that was introduced in Microsoft Windows 7
                and Windows Server 2008R2.

              • 3.0 - The SMBv3.0 protocol that was introduced in Microsoft  Windows  8
                and Windows Server 2012.

              • 3.02 or 3.0.2 - The SMBv3.0.2 protocol that was introduced in Microsoft
                Windows 8.1 and Windows Server 2012R2.

              • 3.1.1 or 3.11 - The SMBv3.1.1 protocol that was introduced in Microsoft
                Windows 10 and Windows Server 2016.

              • 3 - The SMBv3.0 protocol version and above.

              • default  -  Tries  to  negotiate the highest SMB2+ version supported by
                both the client and server.

              If no dialect is specified on mount vers=default is used.  To  check  Di‐
              alect refer to /proc/fs/cifs/DebugData

              Note  too  that  while this option governs the protocol version used, not
              all features of each version are available.

              The default since v4.13.5 is for the client and server to  negotiate  the
              highest  possible  version greater than or equal to 2.1. In kernels prior
              to v4.13, the default was 1.0. For kernels between v4.13 and v4.13.5  the
              default is 3.0.

multichannel

　manページを読んでいる限り、一つだけでなく複数のデータをやり取りするための、よくわかってないですが、複数のTCPセッション（複数の通信路）みたいなのを開くっぽいです。これを指定して見ると、大きなファイルを操作していても快適にファイルマネージャとか、レスポンスよくいろんなファイル操作が行える傾向にありました。一つだけの通信路では、やはり厳しいものがあるようです。

max_channels=16

　multichannelのオプジョンと併用して使う項目です。私は欲張って多ければいいというものでもないと思いますが、とりあえず最大の16にしてみています。こうすると、マウント時にセッション確立に時間がかかるようになるようで、ちょっと遅くなりますが、それ以外においては、特に今のところ問題は感じられていません。

note

　以下は、私がman mount.cifsにあった説明の中で気になった部分を抜き出したものです。

       fsc    Enable  local  disk caching using FS-Cache for CIFS. This option could be
              useful to improve performance on  a  slow  link,  heavily  loaded  server
              and/or  network  where  reading from the disk is faster than reading from
              the server (over the network). This could  also  impact  the  scalability
              positively  as  the  number  of  calls to the server are reduced. But, be
              warned that local caching is not suitable for all  workloads,  for  e.g.,
              read-once  type  workloads. So, you need to consider carefully the situa‐
              tion/workload before using this option. Currently, local disk caching  is
              enabled for CIFS files opened as read-only.

              NOTE: This feature is available only in the recent kernels that have been
              built with the kernel config option CONFIG_CIFS_FSCACHE. You also need to
              have  cachefilesd  daemon  installed and running to make the cache opera‐
              tional.


       compress
              EXPERIMENTAL FEATURE Enables over-the-wire message  compression  for  SMB
              3.1.1  or  higher mounts. Mount fails when compress is on and vers is set
              to a version lower than 3.1.1.


       vers=arg
              SMB protocol version. Allowed values are:

              • 1.0 - The classic CIFS/SMBv1 protocol.

              • 2.0 - The SMBv2.002 protocol. This was initially introduced in  Windows
                Vista  Service  Pack  1, and Windows Server 2008. Note that the initial
                release version of Windows Vista spoke  a  slightly  different  dialect
                (2.000) that is not supported.

              • 2.1  -  The SMBv2.1 protocol that was introduced in Microsoft Windows 7
                and Windows Server 2008R2.

              • 3.0 - The SMBv3.0 protocol that was introduced in Microsoft  Windows  8
                and Windows Server 2012.

              • 3.02 or 3.0.2 - The SMBv3.0.2 protocol that was introduced in Microsoft
                Windows 8.1 and Windows Server 2012R2.

              • 3.1.1 or 3.11 - The SMBv3.1.1 protocol that was introduced in Microsoft
                Windows 10 and Windows Server 2016.

              • 3 - The SMBv3.0 protocol version and above.

              • default  -  Tries  to  negotiate the highest SMB2+ version supported by
                both the client and server.

              If no dialect is specified on mount vers=default is used.  To  check  Di‐
              alect refer to /proc/fs/cifs/DebugData

              Note  too  that  while this option governs the protocol version used, not
              all features of each version are available.

              The default since v4.13.5 is for the client and server to  negotiate  the
              highest  possible  version greater than or equal to 2.1. In kernels prior
              to v4.13, the default was 1.0. For kernels between v4.13 and v4.13.5  the
              default is 3.0.


       --verbose
              Print additional debugging information for the mount. Note that this  pa‐
              rameter must be specified before the -o . For example:

                 mount -t cifs //server/share /mnt --verbose -o user=username

       max_channels=arg
              This  option is applicable while using multichannel feature. max_channels
              option allows the user to specify the  number  of  transport  connections
              that  should be establised between client and server up to a limit of 16.
              Using this  option  implicitly  enables  the  multichannel  feature.   If
              max_channels option not specified, multichannel feature defaults to using
              2 connections.

       multichannel
              This  option enables multichannel feature. Multichannel is an SMB3 proto‐
              col feature that allows client to establish  multiple  transport  connec‐
              tions to an SMB server and bind them into a single authenticated SMB ses‐
              sion.  This  feature enhances fault tolerance and increases throughput by
              distributing traffic across several connections. With this  mount  option
              default  is  to use two channels if the server supports multichannel. The
              max_channels parameter can be specified if you desire to  use  more  than
              two channels.

       echo_interval=n
              sets  the  interval  at  which echo requests are sent to the server on an
              idling connection. This setting also affects the time required for a con‐
              nection to an unresponsive server to timeout. Here n is the echo interval
              in seconds. The reconnection happens at twice the value of  the  echo_in‐
              terval  set for an unresponsive server.  If this option is not given then
              the default value of 60 seconds is used.  The minimum tunable value is  1
              second and maximum can go up to 600 seconds.

参考にしたサイトとか

mount.cifs の man ページ（2025年3月25日）

この記事を作った動機#

ちょっとしたまとめ#

特に気になったオプション#

vers=3.11#

multichannel#

max_channels=16#

note#

参考にしたサイトとか#