Mount filesystems
To use a filesystem via the Weka filesystem driver, it has to be mounted on one of the cluster servers. This page describes how this is performed.
There are two methods available for mounting a filesystem in one of the cluster servers:
- 1.Using the traditional method: See below and also refer to Adding Clients (Bare Metal Installation) or Adding Clients (AWS Installation), where first a client is configured and joins a cluster, after which a mount command is executed.
- 2.Using the Stateless Clients feature: See Mounting Filesystems Using the Stateless Clients Feature below, which simplifies and improves the management of clients in the cluster and eliminates the Adding Clients process.
Note: Using the mount command as explained below first requires the installation of the Weka client, configuring the client, and joining it to a Weka cluster.
To mount a filesystem on one of the cluster servers, let’s assume the cluster has a filesystem called
demo. To add this filesystem to a server, SSH into one of the servers and run the mount command as the root user, as follows:mkdir -p /mnt/weka/demo
mount -t wekafs demo /mnt/weka/demo
The general structure of the
mount command for a Weka filesystem is as follows:mount -t wekafs [-o option[,option]...]] <fs-name> <mount-point>
Two options for mounting a filesystem on a cluster client are read cache and write cache. Refer to the descriptions in the links below to understand the differences between these modes:
The Stateless Clients feature defers the process of joining the cluster until the mount is performed. They are simplifying and improving the management of clients in the cluster. It removes tedious client management procedures, which is particularly beneficial in AWS installations where clients may join and leave at high frequency.
Furthermore, it unifies all security aspects in the mount command, eliminating the search for separate credentials at cluster join and mount.
To use the Stateless Clients feature, a Weka agent must be installed. Once this is complete, mounts can be created and configured using the mount command and can be removed from the cluster using the unmount command.
Note: To allow only Weka authenticated users to mount a filesystem, set the filesystem
--auth-required flag to yes. For more information, refer to the Mount authentication for organization filesystems topic.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 | shOn completion, the agent is installed on the client.
Command:
mount -t wekafsUse one of the following command lines to invoke the mount command (note, 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
Name | Type | Value | Limitations | Mandatory | Default |
options | | See Additional Mount Options below. | | | |
backend | String | IP/hostname of a backend container. | Must be a valid name | Yes | |
fs | String | Filesystem name. | Must be a valid name | Yes | |
mount-point | String | Path to mount on the local server. | Must be a valid path-name | Yes | |
Each mount option can be passed by an individual
-o flag to mount.Option | Value | Description | Default | Remount Supported |
readcache | None | Set mode to read cache. | No | Yes |
writecache | None | Set mode to write cache. | Yes | Yes |
dentry_max_age_positive | Number in milliseconds | After the defined time period, every metadata cached entry is refreshed from the system, allowing the server to take into account metadata changes performed by other servers. | 1000 | Yes |
dentry_max_age_negative | Number in milliseconds | Each time a file or directory lookup fails, an entry specifying that the file or directory does not exist is created in the local dentry cache. This entry is refreshed after the defined time, allowing the server to use files or directories created by other servers. | 0 | Yes |
ro | None | Mount filesystem as read-only. | No | Yes |
rw | None | Mount filesystem as read-write. | Yes | Yes |
inode_bits | 32, 64 or auto | Size of the inode in bits, which may be required for 32-bit applications. | Auto | No |
verbose | None | Write debug logs to the console. | No | Yes |
quiet | None | Don't show any logs to console. | No | Yes |
acl | None | Can be defined per mount. Setting POSIX ACLs can change the effective group permissions (via the mask permissions). When ACLs defined but the mount has no ACL, the effective group permissions are granted.) | No | No |
obs_direct | None | No | Yes | |
noatime | None | Do not update inode access times. | No | Yes |
strictatime | None | Always update inode access times. | No | Yes |
relatime | None | Update inode access times only on modification or change, or if inode has been accessed and relatime_threshold has passed. | Yes | Yes |
relatime_threshold | Number in seconds | The time (in seconds) to wait since an inode has been accessed (not modified) before updating the access time. 0 means never update the access time on access only. This option is relevant only if the relatime is on. | 0 (infinite) | Yes |
nosuid | None | Do not take suid/sgid bits into effect. | No | Yes |
nodev | None | Do not interpret character or block special devices. | No | Yes |
noexec | None | Do not allow direct execution of any binaries. | No | Yes |
file_create_mask | Numeric (octal) notation of POSIX permissions | Newly created file permissions are masked with the creation mask. For example, if a user creates a file with permissions=777 but the file_create_mask is 770, the file will be created with 770 permissions. First, the umask is taken into account, followed by the file_create_mask and then the force_file_mode. | 0777 | Yes |
directory_create_mask | Numeric (octal) notation of POSIX permissions | Newly created directory permissions are masked with the creation mask. For example, if a user creates a directory with permissions=777 but the directory_create_mask is 770, the directory will be created with 770 permissions. First, the umask is taken into account, followed by the directory_create_mask and then the force_directory_mode. | 0777 | Yes |
force_file_mode | Numeric (octal) notation of POSIX permissions | Newly created file permissions are logically OR'ed with the mode. For example, if a user creates a file with permissions 770 but the force_file_mode is 775, the resulting file will be created with mode 775. First, the umask is taken into account, followed by the file_create_mask and then the force_file_mode. | 0 | Yes |
force_directory_mode | Numeric (octal) notation of POSIX permissions | Newly created directory permissions are logically OR'ed with the mode. For example, if a user creates a directory with permissions 770 but the force_directory_mode is 775, the resulting directory will be created with mode 775. First, the umask is taken into account, followed by the directory_create_mask and then the force_directory_mode. | 0 | Yes |
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. Option | Value | Description | Default | Remount Supported |
memory_mb=<memory_mb> | Number | Amount of memory to be used by the client (for huge pages) | 1400 MiB | Yes |
num_cores=<frontend-cores> | Number | The number of frontend cores to allocate for the client. Either <num_cores> or<core> can be specified, but not both.If none are specified, the client will be configured with 1 core. If 0 is specified then you must use net=udp. | 1 | No |
core=<core> | Number | Specify explicit cores to be used by the WekaFS client. Multiple cores can be specified. | | No |
net=<netdev>[/<ip>/<bits>[/<gateway>]] | String | This option must be specified for on-premises installation and must not be specified for AWS installations. | | No |
bandwidth_mbps=<bandwidth_mbps> | Number | Maximum network bandwidth in Mb/s, which limits the traffic that the container can send. The bandwidth setting is helpful in deployments like AWS, where the bandwidth is limited but allowed to burst. | Auto-select | Yes |
remove_after_secs=<secs> | Number | The number of seconds without connectivity after which the client will be removed from the cluster.
Minimum value: 60 seconds. | 86,400 seconds (24 hours) | Yes |
traces_capacity_mb=<size-in-mb> | Number | Traces capacity limit in MB. Minimum value: 512 MB. | | No |
reserve_1g_hugepages | None | Controls the page allocation algorithm if to reserve only 2 MB huge pages or also 1 GB ones. | Yes | Yes |
readahead_kb=<readahead> | Number in KB | Controls the readahead per mount (higher readahead better for sequential reads of large files). | 32768 | Yes |
auth_token_path | String | Path to the mount authentication token (per mount). | ~/.weka/auth-token.json | No |
dedicated_mode | full or none | Determine whether DPKD networking dedicates a core ( full) or not (none). none can only be set when the NIC driver supports it. See the DPDK Without Core Dedication section. This option is relevant when using DPDK networking (net=udp is not set). | full | No |
qos_preferred_throughput_mbps | Number | Preferred requests rate for QoS in megabytes per second. | Yes | |
qos_max_throughput_mbps | Number | Maximum requests rate for QoS in megabytes per second.
This option allows bursting above the specified limit but aims to keep this limit on average. | Yes | |
connect_timeout_secs | Number | The timeout, in seconds, for establishing a connection to a single server.
| 10 | Yes |
response_timeout_secs | Number | The timeout, in seconds, waiting for the response from a single server. | 60 | Yes |
join_timeout_secs | Number | The timeout, in seconds, for the client container to join the Weka cluster. | 360 | Yes |
Note: These parameters, if not stated otherwise, are only effective on the first mount command for each client.
Note: 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. E.g., mount -t wekafs -o core=2 -o core=4 -o net=ib0 backend-server-0/my_fs /mnt/wekaExample: On-Premise Installations
mount -t wekafs -o num_cores=1 -o net=ib0 backend-server-0/my_fs /mnt/wekaRunning this command on a server installed with the Weka agent will download the appropriate Weka version from the
ackend-server-0and create a Weka container that allocates a single core and a named network interface (ib0). Then it will join the cluster that backend-server-0 is part of and mount the filesystem my_fs on /mnt/weka.mount -t wekafs -o num_cores=0 -o net=udp backend-server-0/my_fs /mnt/wekaExample: AWS Installations
mount -t wekafs -o num_cores=2 backend1,backend2,backend3/my_fs /mnt/wekaRunning this command on an AWS EC2 instance allocates two cores (multiple-frontends) and attach and configure two ENIs on the new client. The client will attempt to rejoin the cluster via all three backends used 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 an
umount 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.Note: When running in AWS, the instance IAM role is required to provide permissions to several AWS APIs, as described in IAM Role Created in Template.
Note: Memory allocation for a client is predefined. Contact the Weka Support Team when it is necessary to change the amount of memory allocated to a client.
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).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 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 setweka cluster mount-defaults resetweka cluster mount-defaults showTo 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
Option | Value | Description |
qos_max_throughput | Number | Sets the default value for the qos_max_throughput_mbps option, which is the max requests rate for QoS in megabytes per second. |
qos_preferred_throughput | Number | Sets the default value for the qos_preferred_throughput_mbps option, which is the preferred requests rate for QoS in megabytes per second. |
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.Note: When using
wekafs mounts, both clients and backends should use the same type of networking technology (either IB or Ethernet).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.
When you want to determine the VFs IP addresses or when the client resides in a different subnet and routing is needed in the data network, use
net=<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 these options.
- On-premises environment: the Weka system allocates values of these options from the cluster default network (the
weka cluster default-netmust be set before running the mount command). Otherwise, the Weka cluster does not allocate the IP for the client. For more details, see Optional: Configure default data networking.
For example, the following command allocates two cores and a single physical network device (intel0). It will configure two VFs for the device and assign each one of them to one of the frontend processes. The first container will receive a 192.168.1.100 IP address, and the second will use a 192.168.1.101 IP address. Both of the 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
For performance or high availability, it is possible to use more than one physical network device.
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
Multiple NICs can also be configured to achieve redundancy (refer to Weka Networking HA section for more information) in addition to 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. Note 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 only.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
In cases where DPDK cannot be used, it is possible to use WekaFS in UDP mode through the kernel. Use
net=udp in the mount command to set the UDP networking mode, for example:mount -t wekafs -o num_cores=0 -o net=udp backend-server-0/my_fs /mnt/weka
Note: A client in UDP mode cannot be configured in HA mode. However, the client can still work with a highly available cluster.
Note: Providing multiple IPs in the <mgmt-ip> in UDP mode will utilize their network interfaces for more bandwidth (can be useful in RDMA environments), rather than using only one NIC.
Note: This option works when using stateless clients and with OS that supports
systemd (e.g.: RHEL/CentOS 7.2 and up, Ubuntu 16.04 and up, Amazon Linux 2 LTS).Edit
/etc/fstab file to include the filesystem mount entry:- A comma-separated list of backend servers, with the filesystem name
- The mount point
- Filesystem type -
wekafs - Mount options:
- Configure
systemdto wait for theweka-agentservice to come up, and set the filesystem as a network filesystem, e.g.:x-systemd.requires=weka-agent.service,x-systemd.mount-timeout=infinity,_netdev - Any additional
wekafssupported mount option
# create a mount point
mkdir -p /mnt/weka/my_fs
# edit fstab file
vi /etc/fstab
# fstab with weka options (example, change with your desired settings)
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
Reboot the server for the
systemd unit to be created and marked correctly.The filesystem should now be mounted at boot time.
Note: Do not configure this entry for a mounted filesystem before un-mounting it (
umount), as the systemd needs to mark the filesystem as a network filesystem (occurs as part of the reboot). Trying to reboot a server when there is a mounted WekaFS filesystem when setting its fstab configuration might yield a failure to unmount the filesystem and leave the system hanged.Procedure:
- 1.Install
autofson the server using one of the following commands according to your deployment:
- On RedHat 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>.