Mandatory locks support with GlusterFS v3.8

antmascot

Latest version 3.8 from GlusterFS community comes out with the support for Mandatory locks. Please refer the blog post announcing the release to get an overview of all new features delivered with 3.8. This article will be a background cum architectural analysis on mandatory locks feature for GlusterFS and its further possibilities when working under various protocol environments.

Traditional/Advisory locks
Whenever it comes to a situation where file contents are being concurrently accessed by different applications there always raise the Continue reading

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Compiling Linux kernel with Rich ACL support

I don’t know how many of you have heard about Rich ACL or Rich Access Control Lists. Most of you might have heard about NFS protocol i.e, the Network File System protocol. This particular protocol, with its v4.0 and above defines a particular set of ACLS known as NFSv4 ACLs. Rich ACL is a modified or an extended form of NFSv4 ACLs. Let me explain in brief on what do we mean by ACLs.

ACL or Access Control List ?
This is a list of permissions attached to an object. The object can be file, directories and so on. An ACL specifies which users or system processes are granted access to objects, as well as what operations are allowed on given objects.

ACLs and Linux
Linux follows the POSIX 1003.1e draft 17 standard for defining and storing ACLs. Even then in linux, getfacl and setfacl command line utilities do not strictly follow POSIX 1003.2c draft 17, which shows mostly in the way they handle default ACLs. For detailed explanation on how ACLs are defined and how they work in linux, please see http://users.suse.com/~agruen/acl/linux-acls/online/ .

Variations in ACL implementations
The ACL model implemented by the various versions of Windows is more powerful and complex than POSIX ACLs, and differs in several aspects. These differences create interoperability problems on both sides which is a disadvantage for UNIX-like systems. To address this issue, several UNIX-like systems started to support additional ACL models based on version 4 of the the Network File System (NFSv4) protocol specification. Linux is lacking this support so far. Following are some of the differences between various ACLs

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Introducing trashcan for Gluster File System v3.7

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“GlusterFS is a unified, poly-protocol, scale-out filesystem serving many petabytes of data”

This is the one-liner from http://gluster.org for describing the file system in short. GlusterFS community has made a tremendous progress in the world of distributed file systems. With the recent releases for this open-source project, it aims for something big that no other file system in this field can even dream about. Given the fact that it lacks a bit performace in case of small files, GlusterFS put forwards the following features for its next big release, GlusterFS v4.0:

  1. Thousand Node glusterd
  2. DHT scalability
  3. Small file performace improvement
  4. Better caching
  5. Data classification
  6. NSR or new style replication and much more (http://www.gluster.org/community/documentation/index.php/Planning40)

This particular article on GlusterFS is focussed on explaining the newly introduced trash feature in version 3.7. Please read through the following link for a brief introduction to Gluster File system.
http://www.tecmint.com/introduction-to-glusterfs-file-system-and-installation-on-rhelcentos-and-fedora/

What is Trash translator?
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