Mount filesystems

Explore the methods for mounting a filesystem on a client host using the WEKA filesystem driver, including the stateful client and stateless client methods.

Overview

There are two methods available for mounting a filesystem on a client host:

• Stateful client: This method involves the following steps:

  • Install the WEKA client on the host.

  • Configure the client according to your requirements.

  • Join the client in a WEKA cluster.

  • Once the above steps are completed, you can mount the filesystem. For detailed instructions, see Mount a filesystem using the stateful client method.

• Stateless client: This method simplifies client management in the cluster by eliminating the need for the adding clients' process. For detailed instructions on how to use this feature to mount filesystems, see Mount a filesystem using the stateless client method.

If you need to mount a single client to multiple clusters, see Mount filesystems from multiple clusters on a single client.

Mount a filesystem using the stateful client method

Before using the mount command, you must install the WEKA client, configure it, and join it to a WEKA cluster. This process involves adding clients, which can be done either for bare metal installation or as part of the WEKA deployment on one of the supported clouds.

Assuming the cluster has a filesystem named demo, you can add this filesystem to a server by SSHing into one of the servers and running the mount command as the root user:

mkdir -p /mnt/weka/demo
mount -t wekafs demo /mnt/weka/demo

The general syntax of the mount command for a WEKA filesystem is:

mount -t wekafs [-o option[,option]...] <fs-name> <mount-point>

When mounting a filesystem on a cluster client, you have two options: read cache and write cache. See the respective sections to understand the differences between these modes.

Related topics

WEKA client and mount modes

Add clients (on bare-metal servers)

Add clients (on AWS deployment)

Add clients (on Azure deployment)

Add clients (on GCP deployment)

Mount a filesystem using the stateless client method

The stateless client feature enhances cluster management by deferring the client’s joining process until the filesystem mount is performed. This simplification is especially advantageous in cloud deployments, where client turnover can be high.

This feature also consolidates all security aspects into the mount command, eliminating the need to search for separate credentials during cluster join and mount operations.

To use the stateless client feature, a WEKA agent must be installed. Once this is done, the mount command can be used to create and configure mounts. If needed, existing mounts can be removed from the cluster using the unmount command.

For added security, the filesystem can be configured to only allow mounts by WEKA authenticated users by setting the --auth-required flag to yes. For more details, see Mount authentication for organization filesystems.

Assuming the WEKA cluster is using the backend IP of 1.2.3.4, running the following command as root on a client will install the agent:

curl http://1.2.3.4:14000/dist/v1/install | sh

On completion, the agent is installed on the client.

Run the mount command

Command: mount -t wekafs

Use one of the following command lines to invoke the mount command. The delimiter between the server and filesystem can be either :/ or /:

mount -t wekafs -o <options> <backend0>[,<backend1>,...,<backendN>]/<fs> <mount-point>

mount -t wekafs -o <options> <backend0>[,<backend1>,...,<backendN>]:/<fs> <mount-point>

Parameters

Mount command options

Each mount option can be passed by an individual -o flag to mount.

For all clients types

Remount of general options

You can remount using the mount options marked as Remount Supported in the above table (mount -o remount).

When a mount option has been explicitly changed, you must set it again in the remount operation to ensure it retains its value. For example, if you mount with ro, a remount without it changes the mount option to the default rw. If you mount with rw, it is not required to re-specify the mount option because this is the default.

Additional mount options using the stateless clients feature

These parameters, if not stated otherwise, are only effective on the first mount command for each client.

By default, the command selects the optimal core allocation for WEKA. If necessary, multiple core parameters can be used to allocate specific cores to the WekaFS client. For example, mount -t wekafs -o core=2 -o core=4 -o net=ib0 backend-server-0/my_fs /mnt/weka

Example: On-Premise Installations

mount -t wekafs -o num_cores=1 -o net=ib0 backend-server-0/my_fs /mnt/weka

Running this command on a server installed with the Weka agent downloads the appropriate WEKA version from the backend-server-0and creates a WEKA container that allocates a single core and a named network interface (ib0). Then it joins the cluster that backend-server-0 is part of and mounts the filesystem my_fs on /mnt/weka.

mount -t wekafs -o num_cores=0 -o net=udp backend-server-0/my_fs /mnt/weka

Running this command uses UDP mode (usually selected when the use of DPDK is not available).

Example: AWS Installations

mount -t wekafs -o num_cores=2 backend1,backend2,backend3/my_fs /mnt/weka

Running this command on an AWS EC2 instance allocates two cores (multiple-frontends), attaches and configures two ENIs on the new client. The client attempts to rejoin the cluster through all three backends specified in the command line.

For stateless clients, the first mount command installs the weka client software and joins the cluster). Any subsequent mount command, can either use the same syntax or just the traditional/per-mount parameters as defined in Mounting Filesystems since it is not necessary to join a cluster.

It is now possible to access Weka filesystems via the mount-point, e.g., by cd /mnt/weka/ command.

After the execution of anumount command, which unmounts the last Weka filesystem, the client is disconnected from the cluster and will be uninstalled by the agent. Consequently, executing a new mount command requires the specification of the cluster, cores, and networking parameters again.

When running in AWS, the instance IAM role must provide permissions to several AWS APIs (see the IAM role created in template section).

Memory allocation for a client is predefined. To change the memory allocation, contact the Customer Success Team.

Remount of stateless clients options

Mount options marked as Remount Supported in the above table can be remounted (using mount -o remount). When a mount option is not set in the remount operation, it will retain its current value. To set a mount option back to its default value, use the default modifier (e.g., memory_mb=default).

Set mount option default values

The defaults of the mount options qos_max_throughput_mbps and qos_preferred_throughput_mbps have no limit.

The cluster admin can set these default values to meet the organization's requirements, reset them to the initial default values (no limit), or show the existing values.

The mount option defaults are only relevant for new mounts performed and do not influence the existing ones.

Commands:

weka cluster mount-defaults set

weka cluster mount-defaults reset

weka cluster mount-defaults show

To set the mount option default values, run the following command:

weka cluster mount-defaults set [--qos-max-throughput qos-max-throughput] [--qos-preferred-throughput qos-preferred-throughput]

Parameters

Advanced network configuration by mount options

When using a stateless client, it is possible to alter and control many different networking options, such as:

• Virtual functions

• IPs

• Gateway (in case the client is on a different subnet)

• Physical network devices (for performance and HA)

• UDP mode

Use -o net=<netdev> mount option with the various modifiers as described below.

<netdev> is either the name, MAC address, or PCI address of the physical network device (can be a bond device) to allocate for the client.

When using wekafs mounts, both clients and backends should use the same type of networking technology (either IB or Ethernet).

IP, subnet, gateway, and virtual functions

For higher performance, the usage of multiple Frontends may be required. When using a NIC other than Mellanox or Intel E810 or mounting a DPDK client on a VM, it is required to use SR-IOV to expose a VF of the physical device to the client. Once exposed, it can be configured via the mount command.

To assign the VF IP addresses or when the client resides in a different subnet and routing is needed in the data network, usenet=<netdev>/[ip]/[bits]/[gateway].

ip, bits, gateway are optional. If these options are not provided, the WEKA system performs one of the following depending on the environment:

• Cloud environment: The WEKA system deduces the values of the ip, bits, gateway options.

• On-premises environment: The WEKA system allocates values to the ip, bits, gateway options based on the cluster default network. Failure to set the default network may result in the WEKA cluster failing to allocate an IP address for the client.

  Ensure that the WEKA cluster default data networking is configured prior to running the mount command. For details, see Configure default data networking (optional).

Example: allocate two cores and a single physical network device (intel0)

The following command configures two VFs for the device and assign each one of them to one of the frontend processes. The first container receives a 192.168.1.100 IP address, and the second uses a 192.168.1.101 IP address. Both IPs have 24 network mask bits and a default gateway of 192.168.1.254.

mount -t wekafs -o num_cores=2 -o net=intel0/192.168.1.100+192.168.1.101/24/192.168.1.254 backend1/my_fs /mnt/weka

Multiple physical network devices for performance and HA

For performance or high availability, it is possible to use more than one physical network device.

Using multiple physical network devices for better performance

It's easy to saturate the bandwidth of a single network interface when using WekaFS. For higher throughput, it is possible to leverage multiple network interface cards (NICs). The -o net notation shown in the examples above can be used to pass the names of specific NICs to the WekaFS server driver.

For example, the following command will allocate two cores and two physical network devices for increased throughput:

mount -t wekafs -o num_cores=2 -o net=mlnx0 -o net=mlnx1 backend1/my_fs /mnt/weka

Using multiple physical network devices for HA configuration

Multiple NICs can also be configured to achieve redundancy (for details, see the WEKA networking HA section) and higher throughput for a complete, highly available solution. For that, use more than one physical device as previously described, and also, specify the client management IPs using -o mgmt_ip=<ip>+<ip2> command-line option.

For example, the following command will use two network devices for HA networking and allocate both devices to four Frontend processes on the client. The modifier ha is used here, which stands for using the device on all processes.

mount -t wekafs -o num_cores=4 -o net:ha=mlnx0,net:ha=mlnx1 backend1/my_fs -o mgmt_ip=10.0.0.1+10.0.0.2 /mnt/weka

Advanced mounting options for multiple physical network devices

With multiple Frontend processes (as expressed by -o num_cores), it is possible to control what processes use what NICs. This can be accomplished through the use of special command line modifiers called slots. In WekaFS, slot is synonymous with a process number. Typically, the first WekaFS Frontend process will occupy slot 1, then the second - slot 2 and so on.

Examples of slot notation include s1, s2, s2+1, s1-2, slots1+3, slot1, slots1-4 , where - specifies a range of devices, while + specifies a list. For example, s1-4 implies slots 1, 2, 3, and 4, while s1+4 specifies slots 1 and 4.

For example, in the following command, mlnx0 is bound to the second Frontend process whilemlnx1 to the first one for improved performance.

mount -t wekafs -o num_cores=2 -o net:s2=mlnx0,net:s1=mlnx1 backend1/my_fs /mnt/weka

For example, in the following HA mounting command, two cores (two Frontend processes) and two physical network devices (mlnx0, mlnx1) are allocated. By explicitly specifying s2+1, s1-2 modifiers for network devices, both devices will be used by both Frontend processes. Notation s2+1 stands for the first and second processes, while s1-2 stands for the range of 1 to 2, and are effectively the same.

mount -t wekafs -o num_cores=2 -o net:s2+1=mlnx0,net:s1-2=mlnx1 backend1/my_fs -o mgmt_ip=10.0.0.1+10.0.0.2 /mnt/weka

UDP mode

If DPDK cannot be used, you can use the WEKA filesystem UDP networking mode through the kernel (for details about UDP mode. see the WEKA networking section). Use net=udp in the mount command to set the UDP networking mode, for example:

mount -t wekafs -o net=udp backend-server-0/my_fs /mnt/weka

A client in UDP mode cannot be configured in HA mode. However, the client can still work with a highly available cluster.

Providing multiple IPs in the <mgmt-ip> in UDP mode uses their network interfaces for more bandwidth, which can be useful in RDMA environments rather than using only one NIC.

Mount a filesystem using fstab

Using the fstab (filesystem table) enables automatic remount after reboot. It applies to stateless clients running on an OS that supports systemd, such as RHEL/CentOS 7.2 and up, Ubuntu 16.04 and up, and Amazon Linux 2 LTS.

Before you begin

If the mount point you want to set in the fstab is already mounted, unmount it before setting the fstab file.

Procedure

1. Remove the /etc/init.d/weka-agent file.

2. Create a file named weka-agent.service with the following content and save it in /etc/systemd/system.

weka-agent.service

[Unit]
Description=WEKA Agent Service
Wants=network.target network-online.target
After=network.target network-online.target rpcbind.service
Documentation=http://docs.weka.io
Before=remote-fs-pre.target remote-fs.target

[Service]
Type=simple
ExecStart=/usr/bin/weka --agent
Restart=always
WorkingDirectory=/
EnvironmentFile=/etc/environment
# Increase the default a bit in order to allow many simultaneous
# files to be monitored, we might need a lot of fds.
LimitNOFILE=65535

[Install]
RequiredBy=remote-fs-pre.target remote-fs.target

1. Run the following command:

systemctl daemon-reload; systemctl enable --now weka-agent.service

1. Create a mount point. Example: mkdir -p /mnt/weka/my_fs

2. Edit /etc/fstab file.

fstab structure

<backend servers/my_fs> <mount point> <filesystem type> <mount options> <systemd mount options>  0     0

fstab example

backend-0,backend-1,backend-3/my_fs /mnt/weka/my_fs  wekafs  num_cores=1,net=eth1,x-systemd.requires=weka-agent.service,x-systemd.mount-timeout=infinity,_netdev   0       0

fstab structure descriptions

• Backend servers/my_fs: A comma-separated list of backend servers with the filesystem name

• Mount point: If the client mounts multiple clusters, specify a unique name for each client container. Example: For two client containers, set container_name=client1 and container_name=client2.

• Filesystem type: wekafs

• Mount options:

  • See Additional mount options using the stateless clients feature.

  • Systemd mount options: x-systemd.after=weka-agent.service,x-systemd.mount-timeout=infinity,_netdev You can set the mount-timeout based on your preferences, such as 180 seconds. This flexibility allows you to customize the timeout according to your specific system needs.

1. Mount the the filesystem to test the fstab setting by running the command, for example: mount /mnt/weka/my_fs

2. To test the fstab implementation, reboot the server. WEKA creates the mounts for the next boot.

The filesystem is mounted automatically after server reboot.

Mount a filesystem using autofs

Procedure:

1. Install autofs on the server using one of the following commands according to your deployment:

• On Red Hat or CentOS:

yum install -y autofs

• On Debian or Ubuntu:

apt-get install -y autofs

2. To create the autofs configuration files for Weka filesystems, do one of the following depending on the client type:

• For a stateless client, run the following commands (specify the backend names as parameters):

echo "/mnt/weka   /etc/auto.wekafs -fstype=wekafs,num_cores=1,net=<netdevice>" > /etc/auto.master.d/wekafs.autofs
echo "*   <backend-1>,<backend-2>/&" > /etc/auto.wekafs

• For a stateful client (traditional), run the following commands:

echo "/mnt/weka   /etc/auto.wekafs -fstype=wekafs" > /etc/auto.master.d/wekafs.autofs
echo "*   &" > /etc/auto.wekafs

3. Restart the autofs service:

service autofs restart

4. The configuration is distribution-dependent. Verify that the service is configured to start automatically after restarting the server. Run the following command: systemctl is-enabled autofs. If the output is enabled the service is configured to start automatically.

Example: In Amazon Linux, you can verify that the autofs service is configured to start automatically by running the command chkconfig. If the output is on for the current runlevel (you can check with therunlevel command), autofs is enabled upon restart.

# chkconfig | grep autofs
autofs         0:off 1:off 2:off 3:on 4:on 5:on 6:off

Once you complete this procedure, it is possible to access Weka filesystems using the command cd /mnt/weka/<fs-name>.