- Fs 2 6 0 – Note Manager Interview Questions
- Fs 2 6 0 – Note Manager Interview Question And Answer
- Fs 2 6 0 – Note Manager Interview Question
- Fs 2 6 0 – Note Manager Interview Questions And Answers
- The Hadoop Distributed File System (HDFS) is a distributed file system designed to run on commodity hardware. It has many similarities with existing distributed file systems. However, the differences from other distributed file systems are significant. HDFS is highly fault-tolerant and is designed to be deployed on low-cost hardware.
- Academia.edu is a platform for academics to share research papers.
You can access gluster volumes in multiple ways. You can use GlusterNative Client method for high concurrency, performance and transparentfailover in GNU/Linux clients. You can also use NFS v3 to access glustervolumes. Extensive testing has been done on GNU/Linux clients and NFSimplementation in other operating system, such as FreeBSD, and Mac OS X,as well as Windows 7 (Professional and Up) and Windows Server 2003.Other NFS client implementations may work with gluster NFS server.
You can use CIFS to access volumes when using Microsoft Windows as wellas SAMBA clients. For this access method, Samba packages need to bepresent on the client side.
If you are using satelitte6 and have Content Views with custom channel names or different from the one used of the container base image (by default 7Server) remember to add the -releasever=xyz modifier to all your yum commands. Note:. Original: This is the original software/driver released with the computer. It is current and recommended for use. Updated: This software/driver is newer than the original version.
Gluster Native Client
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The Gluster Native Client is a FUSE-based client running in user space.Gluster Native Client is the recommended method for accessing volumeswhen high concurrency and high write performance is required.
This section introduces the Gluster Native Client and explains how toinstall the software on client machines. This section also describes howto mount volumes on clients (both manually and automatically) and how toverify that the volume has mounted successfully.
Installing the Gluster Native Client
Before you begin installing the Gluster Native Client, you need toverify that the FUSE module is loaded on the client and has access tothe required modules as follows:
- Add the FUSE loadable kernel module (LKM) to the Linux kernel:
# modprobe fuse
- Verify that the FUSE module is loaded:
# dmesg | grep -i fuse
fuse init (API version 7.13)
Installing on Red Hat Package Manager (RPM) Distributions
To install Gluster Native Client on RPM distribution-based systems
- Install required prerequisites on the client using the following command:
$ sudo yum -y install openssh-server wget fuse fuse-libs openib libibverbs
- Ensure that TCP and UDP ports 24007 and 24008 are open on all Gluster servers. Apart from these ports, you need to open one port for each brick starting from port 49152 (instead of 24009 onwards as with previous releases). The brick ports assignment scheme is now compliant with IANA guidelines. For example: if you have five bricks, you need to have ports 49152 to 49156 open.You can use the following chains with iptables:
- Download the latest glusterfs, glusterfs-fuse, and glusterfs-rdma RPM files to each client. The glusterfs package contains the Gluster Native Client. The glusterfs-fuse package contains the FUSE translator required for mounting on client systems and the glusterfs-rdma packages contain OpenFabrics verbs RDMA module for Infiniband.You can download the software at GlusterFS download page.
- Install Gluster Native Client on the client.
Note The package versions listed in the example below may not be the latest release. Please refer to the download page to ensure that you have the recently released packages.
Note:The RDMA module is only required when using Infiniband.
Installing on Debian-based Distributions
To install Gluster Native Client on Debian-based distributions
- Install OpenSSH Server on each client using the following command:
$ sudo apt-get install openssh-server vim wget
- Download the latest GlusterFS .deb file and checksum to each client.You can download the software at GlusterFS download page.
- For each .deb file, get the checksum (using the following command) and compare it against the checksum for that file in the md5sum file.
$ md5sum GlusterFS_DEB_file.deb
The md5sum of the packages is available at: GlusterFS download page - Uninstall GlusterFS v3.1 (or an earlier version) from the client using the following command:
$ sudo dpkg -r glusterfs
(Optional) Run$ sudo dpkg -purge glusterfs
to purge theconfiguration files. - Install Gluster Native Client on the client using the following command:
$ sudo dpkg -i GlusterFS_DEB_file
For example:$ sudo dpkg -i glusterfs-3.8.x.deb
- Ensure that TCP and UDP ports 24007 and 24008 are open on all Gluster servers. Apart from these ports, you need to open one port for each brick starting from port 49152 (instead of 24009 onwards as with previous releases). The brick ports assignment scheme is now compliant with IANA guidelines. For example: if you have five bricks, you need to have ports 49152 to 49156 open.You can use the following chains with iptables:
Note
If you already have iptable chains, make sure that the aboveACCEPT rules precede the DROP rules. This can be achieved byproviding a lower rule number than the DROP rule.
Performing a Source Installation
To build and install Gluster Native Client from the source code
- Create a new directory using the following commands:
- Download the source code.You can download the source at link.
- Extract the source code using the following command:
# tar -xvzf SOURCE-FILE
- Run the configuration utility using the following command:
# ./configure
The configuration summary shows the components that will be builtwith Gluster Native Client. - Build the Gluster Native Client software using the following commands:
- Verify that the correct version of Gluster Native Client is installed, using the following command:
# glusterfs --version
Mounting Volumes
After installing the Gluster Native Client, you need to mount Glustervolumes to access data. There are two methods you can choose:
Note
Server names selected during creation of Volumes should be resolvablein the client machine. You can use appropriate /etc/hosts entries orDNS server to resolve server names to IP addresses.
Manually Mounting Volumes
- To mount a volume, use the following command:
# mount -t glusterfs HOSTNAME-OR-IPADDRESS:/VOLNAME MOUNTDIR
For example:# mount -t glusterfs server1:/test-volume /mnt/glusterfs
NoteThe server specified in the mount command is only used to fetchthe gluster configuration volfile describing the volume name.Subsequently, the client will communicate directly with theservers mentioned in the volfile (which might not even include theone used for mount).If you see a usage message like 'Usage: mount.glusterfs', mountusually requires you to create a directory to be used as the mountpoint. Run 'mkdir /mnt/glusterfs' before you attempt to run themount command listed above.
Mounting Options
You can specify the following options when using the
mount -t glusterfs
command. Note that you need to separate all optionswith commas.For example:
# mount -t glusterfs -o backupvolfile-server=volfile_server2,use-readdirp=no,volfile-max-fetch-attempts=2,log-level=WARNING,log-file=/var/log/gluster.log server1:/test-volume /mnt/glusterfs
If
backupvolfile-server
option is added while mounting fuse client,when the first volfile server fails, then the server specified inbackupvolfile-server
option is used as volfile server to mount theclient.In
volfile-max-fetch-attempts=X
option, specify the number ofattempts to fetch volume files while mounting a volume. This option isuseful when you mount a server with multiple IP addresses or whenround-robin DNS is configured for the server-name.If
use-readdirp
is set to ON, it forces the use of readdirpmode in fuse kernel moduleAutomatically Mounting Volumes
You can configure your system to automatically mount the Gluster volumeeach time your system starts.
The server specified in the mount command is only used to fetch thegluster configuration volfile describing the volume name. Subsequently,the client will communicate directly with the servers mentioned in thevolfile (which might not even include the one used for mount).
- To mount a volume, edit the /etc/fstab file and add the following line:
HOSTNAME-OR-IPADDRESS:/VOLNAME MOUNTDIR glusterfs defaults,_netdev 0 0
For example:server1:/test-volume /mnt/glusterfs glusterfs defaults,_netdev 0 0
Mounting Options
You can specify the following options when updating the /etc/fstab file.Note that you need to separate all options with commas.
For example:
HOSTNAME-OR-IPADDRESS:/VOLNAME MOUNTDIR glusterfs defaults,_netdev,log-level=WARNING,log-file=/var/log/gluster.log 0 0
Testing Mounted Volumes
To test mounted volumes
- Use the following command:
# mount
If the gluster volume was successfully mounted, the output of themount command on the client will be similar to this example:server1:/test-volume on /mnt/glusterfs type fuse.glusterfs (rw,allow_other,default_permissions,max_read=131072
A better finder rename 8 84 intelkg download free. - Use the following command:
# df
The output of df command on the client will display the aggregatedstorage space from all the bricks in a volume similar to thisexample: - Change to the directory and list the contents by entering the following:
- For example,
You can use NFS v3 to access to gluster volumes. Extensive testing hasbe done on GNU/Linux clients and NFS implementation in other operatingsystem, such as FreeBSD, and Mac OS X, as well as Windows 7(Professional and Up), Windows Server 2003, and others, may work withgluster NFS server implementation.
GlusterFS now includes network lock manager (NLM) v4. NLM enablesapplications on NFSv3 clients to do record locking on files on NFSserver. It is started automatically whenever the NFS server is run.
You must install nfs-common package on both servers and clients (onlyfor Debian-based) distribution.
This section describes how to use NFS to mount Gluster volumes (bothmanually and automatically) and how to verify that the volume has beenmounted successfully.
Using NFS to Mount Volumes
You can use either of the following methods to mount Gluster volumes:
Prerequisite: Install nfs-common package on both servers and clients(only for Debian-based distribution), using the following command:
$ sudo aptitude install nfs-common
Manually Mounting Volumes Using NFS
To manually mount a Gluster volume using NFS
![Manager Manager](https://i0.wp.com/schoolofinternetmarketing.co.in/wp-content/uploads/2019/11/image1.png)
- To mount a volume, use the following command:
# mount -t nfs -o vers=3 HOSTNAME-OR-IPADDRESS:/VOLNAME MOUNTDIR
For example:# mount -t nfs -o vers=3 server1:/test-volume /mnt/glusterfs
NoteGluster NFS server does not support UDP. If the NFS client you areusing defaults to connecting using UDP, the following messageappears:requested NFS version or transport protocol is not supported
.To connect using TCP - Add the following option to the mount command:
-o mountproto=tcp
For example:# mount -o mountproto=tcp -t nfs server1:/test-volume /mnt/glusterfs
To mount Gluster NFS server from a Solaris client
- Use the following command:
# mount -o proto=tcp,vers=3 nfs://HOSTNAME-OR-IPADDRESS:38467/VOLNAME MOUNTDIR
For example:# mount -o proto=tcp,vers=3 nfs://server1:38467/test-volume /mnt/glusterfs
Automatically Mounting Volumes Using NFS
You can configure your system to automatically mount Gluster volumesusing NFS each time the system starts.
To automatically mount a Gluster volume using NFS
- To mount a volume, edit the /etc/fstab file and add the following line:
HOSTNAME-OR-IPADDRESS:/VOLNAME MOUNTDIR nfs defaults,_netdev,vers=3 0 0
For example,server1:/test-volume /mnt/glusterfs nfs defaults,_netdev,vers=3 0 0
NoteGluster NFS server does not support UDP. If the NFS client you areusing defaults to connecting using UDP, the following messageappears:requested NFS version or transport protocol is not supported.
To connect using TCP - Add the following entry in /etc/fstab file :
HOSTNAME-OR-IPADDRESS:/VOLNAME MOUNTDIR nfs defaults,_netdev,mountproto=tcp 0 0
For example,server1:/test-volume /mnt/glusterfs nfs defaults,_netdev,mountproto=tcp 0 0
To automount NFS mounts
Gluster supports *nix standard method of automounting NFS mounts.Update the /etc/auto.master and /etc/auto.misc and restart the autofsservice. After that, whenever a user or process attempts to access thedirectory it will be mounted in the background.
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Testing Volumes Mounted Using NFS
You can confirm that Gluster directories are mounting successfully.
To test mounted volumes Pathfinder: kingmaker mac os.
- Use the mount command by entering the following:
# mount
For example, the output of the mount command on the client willdisplay an entry like the following:server1:/test-volume on /mnt/glusterfs type nfs (rw,vers=3,addr=server1)
- Use the df command by entering the following:
# df
For example, the output of df command on the client will display theaggregated storage space from all the bricks in a volume. - Change to the directory and list the contents by entering the following:
# cd MOUNTDIR
# ls
You can use CIFS to access to volumes when using Microsoft Windows aswell as SAMBA clients. For this access method, Samba packages need to bepresent on the client side. You can export glusterfs mount point as thesamba export, and then mount it using CIFS protocol.
This section describes how to mount CIFS shares on MicrosoftWindows-based clients (both manually and automatically) and how toverify that the volume has mounted successfully.
Note
CIFS access using the Mac OS X Finder is not supported, however, youcan use the Mac OS X command line to access Gluster volumes usingCIFS.
Using CIFS to Mount Volumes
You can use either of the following methods to mount Gluster volumes:
You can also use Samba for exporting Gluster Volumes through CIFSprotocol.
Exporting Gluster Volumes Through Samba
We recommend you to use Samba for exporting Gluster volumes through theCIFS protocol.
To export volumes through CIFS protocol
- Mount a Gluster volume.
- Setup Samba configuration to export the mount point of the Gluster volume.For example, if a Gluster volume is mounted on /mnt/gluster, youmust edit smb.conf file to enable exporting this through CIFS. Opensmb.conf file in an editor and add the following lines for a simpleconfiguration:
Save the changes and start the smb service using your systems initscripts (/etc/init.d/smb [re]start). Abhove steps is needed for doingmultiple mount. If you want only samba mount then in your smb.conf you need to add
Note
To be able mount from any server in the trusted storage pool, you mustrepeat these steps on each Gluster node. For more advancedconfigurations, see Samba documentation.
Manually Mounting Volumes Using CIFS
You can manually mount Gluster volumes using CIFS on MicrosoftWindows-based client machines.
To manually mount a Gluster volume using CIFS
- Using Windows Explorer, choose Tools > Map Network Drive… from the menu. The Map Network Drivewindow appears.
- Choose the drive letter using the Drive drop-down list.
- Click Browse, select the volume to map to the network drive, and click OK.
- Click Finish.
The network drive (mapped to the volume) appears in the Computer window.
Alternatively, to manually mount a Gluster volume using CIFS by going toStart > Run and entering Network path manually.
Automatically Mounting Volumes Using CIFS
You can configure your system to automatically mount Gluster volumesusing CIFS on Microsoft Windows-based clients each time the systemstarts.
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To automatically mount a Gluster volume using CIFS
The network drive (mapped to the volume) appears in the Computer windowand is reconnected each time the system starts.
- Using Windows Explorer, choose Tools > Map Network Drive… from the menu. The Map Network Drivewindow appears.
- Choose the drive letter using the Drive drop-down list.
- Click Browse, select the volume to map to the network drive, and click OK.
- Click the Reconnect at logon checkbox.
- Click Finish.
Testing Volumes Mounted Using CIFS
You can confirm that Gluster directories are mounting successfully bynavigating to the directory using Windows Explorer.
NameNode and DataNodes
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HDFS has a master/slave architecture. An HDFS cluster consists of a single NameNode, a master server that manages the file system namespace and regulates access to files by clients. In addition, there are a number of DataNodes, usually one per node in the cluster, which manage storage attached to the nodes that they run on. HDFS exposes a file system namespace and allows user data to be stored in files. Internally, a file is split into one or more blocks and these blocks are stored in a set of DataNodes. The NameNode executes file system namespace operations like opening, closing, and renaming files and directories. It also determines the mapping of blocks to DataNodes. The DataNodes are responsible for serving read and write requests from the file system’s clients. The DataNodes also perform block creation, deletion, and replication upon instruction from the NameNode.
The NameNode and DataNode are pieces of software designed to run on commodity machines. These machines typically run a GNU/Linux operating system (OS). HDFS is built using the Java language; any machine that supports Java can run the NameNode or the DataNode software. Usage of the highly portable Java language means that HDFS can be deployed on a wide range of machines. A typical deployment has a dedicated machine that runs only the NameNode software. Each of the other machines in the cluster runs one instance of the DataNode software. The architecture does not preclude running multiple DataNodes on the same machine but in a real deployment that is rarely the case.
The existence of a single NameNode in a cluster greatly simplifies the architecture of the system. The NameNode is the arbitrator and repository for all HDFS metadata. The system is designed in such a way that user data never flows through the NameNode.