Where Are Mac Addresses Stored For Future Reference

  1. Where Are Mac Addresses Stored For Future Reference
  2. Where Are Mac Addresses Stored For Future References
  3. Where Are Mac Addresses Stored For Future Reference In Excel
  4. Where Are Mac Addresses Stored For Future Reference Letter
  5. Where Are Mac Addresses Stored For Future Reference Chart

Switches operate by building a reference table of MAC addresses and corresponding switch ports. Based on the destination MAC address, the switch knows which port to forward the frames to. This table is called the context-addressable memory (CAM) table. May 10, 2017 The MAC address, also called the “burned in address,” lives close to the network hardware, independent of the operating system. In Ye Olde Days, the MAC address lived on a dedicated chip. MAC addresses are primarily assigned by device manufacturers, and are therefore often referred to as the burned-in address, or as an Ethernet hardware address, hardware address, or physical address. Each address can be stored in hardware, such as the card's read-only memory, or by a firmware mechanism. Switches operate by building a reference table of MAC addresses and corresponding switch ports. Based on the destination MAC address, the switch knows which port to forward the frames to. This table is called the context-addressable memory (CAM) table. Sewing machine serial number database.

Estimated reading time: 10 minutes

Ideally, very little data is written to a container’s writable layer, and youuse Docker volumes to write data. However, some workloads require you to be ableto write to the container’s writable layer. This is where storage drivers comein.

Docker supports several different storage drivers, using a pluggablearchitecture. The storage driver controls how images and containers are storedand managed on your Docker host.

After you have read the storage driver overview, thenext step is to choose the best storage driver for your workloads. In makingthis decision, there are three high-level factors to consider:

If multiple storage drivers are supported in your kernel, Docker has a prioritized list of which storage driver to use if no storage driver is explicitly configured, assuming that the storage driver meets the prerequisites.

Use the storage driver with the best overall performance and stability in the most usual scenarios.

Docker supports the following storage drivers:

  • overlay2 is the preferred storage driver, for all currently supported Linux distributions, and requires no extra configuration.
  • aufs was the preferred storage driver for Docker 18.06 and older, when running on Ubuntu 14.04 on kernel 3.13 which had no support for overlay2.
  • fuse-overlayfs is preferred only for running Rootless Dockeron a host that does not provide support for rootless overlay2.On Ubuntu and Debian 10, the fuse-overlayfs driver does not need to beused overlay2 works even in rootless mode.See Rootless mode documentation.
  • devicemapper is supported, but requires direct-lvm for production environments, because loopback-lvm, while zero-configuration, has very poor performance. devicemapper was the recommended storage driver for CentOS and RHEL, as their kernel version did not support overlay2. However, current versions of CentOS and RHEL now have support for overlay2, which is now the recommended driver.
  • The btrfs and zfs storage drivers are used if they are the backingfilesystem (the filesystem of the host on which Docker is installed).These filesystems allow for advanced options, such as creating “snapshots”,but require more maintenance and setup. Each of these relies on the backingfilesystem being configured correctly.
  • The vfs storage driver is intended for testing purposes, and for situationswhere no copy-on-write filesystem can be used. Performance of this storagedriver is poor, and is not generally recommended for production use.

Docker’s source code defines the selection order. You can see the order atthe source code for Docker Engine - Community 20.10

If you run a different version of Docker, you can use the branch selector at the top of the file viewer to choose a different branch.

Some storage drivers require you to use a specific format for the backing filesystem. If you have external requirements to use a specific backing filesystem, this may limit your choices. See Supported backing filesystems.

After you have narrowed down which storage drivers you can choose from, your choice is determined by the characteristics of your workload and the level of stability you need. See Other considerationsfor help in making the final decision.

NOTE: Your choice may be limited by your operating system and distribution. For instance, aufs is only supported on Ubuntu and Debian, and may require extra packages to be installed, while btrfs is only supported on SLES, which is only supported with DockerEnterprise. See Support storage drivers per Linux distribution for more information.

Supported storage drivers per Linux distribution

At a high level, the storage drivers you can use is partially determined bythe Docker edition you use.

In addition, Docker does not recommend any configuration that requires you todisable security features of your operating system, such as the need to disableselinux if you use the overlay or overlay2 driver on CentOS.

Docker Engine - Community

For Docker Engine - Community, only some configurations are tested, and your operatingsystem’s kernel may not support every storage driver. In general, the followingconfigurations work on recent versions of the Linux distribution:

Linux distributionRecommended storage driversAlternative drivers
Docker Engine - Community on Ubuntuoverlay2 or aufs (for Ubuntu 14.04 running on kernel 3.13)overlay¹, devicemapper², zfs, vfs
Docker Engine - Community on Debianoverlay2 (Debian Stretch), aufs or devicemapper (older versions)overlay¹, vfs
Docker Engine - Community on CentOSoverlay2overlay¹, devicemapper², zfs, vfs
Docker Engine - Community on Fedoraoverlay2overlay¹, devicemapper², zfs, vfs

¹) The overlay storage driver is deprecated, and will be removed in a futurerelease. It is recommended that users of the overlay storage driver migrate to overlay2.

²) The devicemapper storage driver is deprecated, and will be removed in a futurerelease. It is recommended that users of the devicemapper storage driver migrateto overlay2.

Where Are Mac Addresses Stored For Future Reference

Note

The comparison table above is not applicable for Rootless mode.For the drivers available in Rootless mode, see the Rootless mode documentation.

When possible, overlay2 is the recommended storage driver. When installingDocker for the first time, overlay2 is used by default. Previously, aufs wasused by default when available, but this is no longer the case. If you want touse aufs on new installations going forward, you need to explicitly configureit, and you may need to install extra packages, such as linux-image-extra.See aufs.

On existing installations using aufs, it is still used.

When in doubt, the best all-around configuration is to use a modern Linuxdistribution with a kernel that supports the overlay2 storage driver, and touse Docker volumes for write-heavy workloads instead of relying on writing datato the container’s writable layer.

The vfs storage driver is usually not the best choice. Before using the vfsstorage driver, be sure to read aboutits performance and storage characteristics and limitations.

Expectations for non-recommended storage drivers: Commercial support isnot available for Docker Engine - Community, and you can technically use any storage driverthat is available for your platform. For instance, you can use btrfs withDocker Engine - Community, even though it is not recommended on any platform forDocker Engine - Community, and you do so at your own risk.

Where Are Mac Addresses Stored For Future References

The recommendations in the table above are based on automated regressiontesting and the configurations that are known to work for a large number ofusers. If you use a recommended configuration and find a reproducible issue,it is likely to be fixed very quickly. If the driver that you want to use isnot recommended according to this table, you can run it at your own risk. Youcan and should still report any issues you run into. However, such issueshave a lower priority than issues encountered when using a recommendedconfiguration.

Docker Desktop for Mac and Docker Desktop for Windows

Docker Desktop for Mac and Docker Desktop for Windows are intended for development, ratherthan production. Modifying the storage driver on these platforms is notpossible.

Supported backing filesystems

For

With regard to Docker, the backing filesystem is the filesystem where/var/lib/docker/ is located. Some storage drivers only work with specificbacking filesystems.

Storage driverSupported backing filesystems
overlay2, overlayxfs with ftype=1, ext4
fuse-overlayfsany filesystem
aufsxfs, ext4
devicemapperdirect-lvm
btrfsbtrfs
zfszfs
vfsany filesystem

Where Are Mac Addresses Stored For Future Reference In Excel

Other considerations

Suitability for your workload

Where Are Mac Addresses Stored For Future Reference Letter

Among other things, each storage driver has its own performance characteristicsthat make it more or less suitable for different workloads. Consider thefollowing generalizations:

  • overlay2, aufs, and overlay all operate at the file level rather thanthe block level. This uses memory more efficiently, but the container’swritable layer may grow quite large in write-heavy workloads.
  • Block-level storage drivers such as devicemapper, btrfs, and zfs performbetter for write-heavy workloads (though not as well as Docker volumes).
  • For lots of small writes or containers with many layers or deep filesystems,overlay may perform better than overlay2, but consumes more inodes, whichcan lead to inode exhaustion.
  • btrfs and zfs require a lot of memory.
  • zfs is a good choice for high-density workloads such as PaaS.

More information about performance, suitability, and best practices is availablein the documentation for each storage driver.

Shared storage systems and the storage driver

If your enterprise uses SAN, NAS, hardware RAID, or other shared storagesystems, they may provide high availability, increased performance, thinprovisioning, deduplication, and compression. In many cases, Docker can work ontop of these storage systems, but Docker does not closely integrate with them.

Where Are Mac Addresses Stored For Future Reference Chart

Each Docker storage driver is based on a Linux filesystem or volume manager. Besure to follow existing best practices for operating your storage driver(filesystem or volume manager) on top of your shared storage system. Forexample, if using the ZFS storage driver on top of a shared storage system, besure to follow best practices for operating ZFS filesystems on top of thatspecific shared storage system.

Stability

For some users, stability is more important than performance. Though Dockerconsiders all of the storage drivers mentioned here to be stable, some are newerand are still under active development. In general, overlay2, aufs, overlay,and devicemapper are the choices with the highest stability.

Test with your own workloads

You can test Docker’s performance when running your own workloads on differentstorage drivers. Make sure to use equivalent hardware and workloads to matchproduction conditions, so you can see which storage driver offers the bestoverall performance.

Check your current storage driver

The detailed documentation for each individual storage driver details all of theset-up steps to use a given storage driver.

To see what storage driver Docker is currently using, use docker info and lookfor the Storage Driver line:

To change the storage driver, see the specific instructions for the new storagedriver. Some drivers require additional configuration, including configurationto physical or logical disks on the Docker host.

Important: When you change the storage driver, any existing images andcontainers become inaccessible. This is because their layers cannot be usedby the new storage driver. If you revert your changes, you canaccess the old images and containers again, but any that you pulled orcreated using the new driver are then inaccessible.

Related information

container, storage, driver, aufs, btrfs, devicemapper, zfs, overlay, overlay2