[3] It was originally written for SGI's IRIX operating system, but in 1998 it was ported to Linux since the open source code provided a more convenient development platform. Thanks, Aaron. I have configured glusterfs in replication mode but want to use gfs2 instead of xfs. Since Red Hat Enterprise Linux version 5.3, Red Hat Enterprise Linux Advanced Platform has included support for GFS at no additional cost. Please note, although ZFS on Solaris supports encryption, the current version of ZFS on Linux does not. The GFS2 utilities mount and unmount the meta filesystem as required, behind the scenes. Developers forked OpenGFS from the last public release of GFS and then further enhanced it to include updates allowing it to work with OpenDLM. If you'd like to contribute REST access via translators. For example: The other main difference, and one that is shared by all similar cluster filesystems, is that the cache control mechanism, known as glocks (pronounced Gee-locks) for GFS/GFS2, has an effect across the whole cluster.

Fencing is used to ensure that a node which the cluster believes to be failed cannot suddenly start working again while another node is recovering the journal for the failed node.

But what would be a behavior when GlusterFS is over? Using GFS2 in a cluster requires hardware to allow access to the shared storage, and a lock manager to control access to the storage. Depending upon the choice of SAN, it may be possible to combine this, but normal practice[citation needed] involves separate networks for the DLM and storage. Red Hat Enterprise Linux 5.2 included GFS2 as a kernel module for evaluation purposes.

These two technologies combined provide a very stable, highly available and integral storage solution. Most of the data remains in place. Nice article. That turns off glusters io cache which seems to insulate the VM’s from the lack of O_DIRECT, so you can leav the vm caching off. The DLM requires an IP based network over which to communicate. I am concerned about performance?

Of course, doing these operations from multiple nodes will work as expected, but due to the requirement to flush caches frequently, it will not be very efficient. Journaled files in GFS have a number of restrictions placed upon them, such as GlusterFS is then set up on top of these 3 volumes to provide replication to the second hardware node. Adding another layer (GlusterFs) would create overhead. For this storage architecture to work, two individual hardware nodes should have the same amount of local storage available presented as a ZFS pool. If GFS2 is possible with glusterfs, can some one give link to documentation. Have you been able to create a gluster volume from a cifs-mounted zfs dataset? The network and filesystem are not the problem….

against a mirrored pair of GlusterFS on top of (any) filesystem, including ZFS. content.

GFS and GFS2 are both journaled file systems; and GFS2 supports a similar set of journaling modes as ext3.

GlusterFS is a distributed file system which can be installed on multiple servers and clients to provide redundant storage. In DF mode, the inode is allowed to cache metadata only, and again it must not be dirty.

I did a post on performance and my experience with GlusterFS. In GFS the journals are disk extents, in GFS2 the journals are just regular files. As GlusterFS just uses the filesystem and all it’s storage there should be no problem.

The server also handles client connections with it’s built in NFS service. GlusterFS is a distributed file system that can be used to span and replicate data volumes across multiple Gluster hosts over a network. Here what i did: I ran a simple "rsync benchmark" with a lot of files to compare the write performance for small files. For the general concept, see, Compatibility and the GFS2 meta filesystem, Red Hat Enterprise Linux Advanced Platform, "Symmetric Cluster Architecture and Component Technical Specifications", "The Global File System: A File System for Shared Disk Storage", OpenGFS Data sharing with a GFS storage cluster, "Testing and verification of cluster filesystems", Red Hat Enterprise Linux 6 - Global File System 2, https://en.wikipedia.org/w/index.php?title=GFS2&oldid=986858815, Distributed file systems supported by the Linux kernel, Virtualization-related software for Linux, Articles containing potentially dated statements from 2009, All articles containing potentially dated statements, Articles with unsourced statements from July 2010, Articles containing potentially dated statements from 2010, Creative Commons Attribution-ShareAlike License, Hashed (small directories stuffed into inode), attribute modification (ctime), modification (mtime), access (atime), No-atime, journaled data (regular files only), inherit journaled data (directories only), synchronous-write, append-only, immutable, exhash (dirs only, read only), Leases are not supported with the lock_dlm (cluster) lock module, but they are supported when used as a local filesystem, The metadata filesystem (really a different root) – see, GFS2 specific trace points have been available since kernel 2.6.32, The XFS-style quota interface has been available in GFS2 since kernel 2.6.33, Caching ACLs have been available in GFS2 since 2.6.33, GFS2 supports the generation of "discard" requests for thin provisioning/SCSI TRIM requests, GFS2 supports I/O barriers (on by default, assuming underlying device supports it. Configure the required ZFS datasets on each node, such as binaries, homes and backup in this example. LinuxQuestions.org is looking for people interested in writing This can be used instead of the data=journal mount option which ext3 supports (and GFS/GFS2 does not). "Global File System" redirects here. And if you are running glusterfs on top of ZFS, hosting KVM images its even less obvious and you will get weird i/o errors until you switch the kvm to use caching. In order that operations which change an inode's data or metadata do not interfere with each other, an EX lock is used. As of 2010[update], GFS2 does not yet support data=journal mode, but it does (unlike GFS) use the same on-disk format for both regular and journaled files, and it also supports the same journaled and inherit-journal attributes. We continue to try GlusterFS about every 6 months, hoping this file replication issue has been resolved, but no joy. Each of the four modes maps directly to a DLM lock mode. This forum is for the discussion of Linux Software used in a server related context.

I fiddled a lot with dm-cache, bcache and EnhanceIO – managed to wreck a few filesystems, before settling on zfs. In computing, the Global File System 2 or GFS2 is a shared-disk file system for Linux computer clusters. Clients can mount storage from one or more servers and employ caching to help with performance. http://www.gluster.org/community/documentation/index.php/Libgfapi_with_qemu_libvirt#Tuning_the_volume_for_virt-store. Much better to have it integrated in the fs and of course the management/reporting tools are much better. Some stem from the difficulty of implementing those features efficiently in a clustered manner. Each inode on the filesystem has two glocks associated with it. Far more scalable. GFS2 has no disconnected operating-mode, and no client or server roles. The number of nodes which may mount the filesystem at any one time is limited by the number of available journals. I’m also experimenting with a two-node proxmox cluster, which has zfs as backend local storage and glusterfs on top of that for replication.I have successfully done live migration to my vms which reside on glusterfs storage. Set up ZFS on both physical nodes with the same amount of storage, presented as a single ZFS storage pool. The problematic resource with 1M of files is a single directory, or a complete filesystem? One of the big advantages Im finding with zfs, is how easy it makes adding SSD’s as journal logs and caches. See this post for setting up ZFS on Ubuntu. I want to ask your opinion about glusterfs and extended attributes on zfs.I read several articles on the inet which suggest to not use the combination of glusterfs + zfs and use glusterfs + xfs for better results. That’s not a large enough section of data to make a worth-while benchmark. You’ll want to update your post. This provides redundant storage and allows recovery from a single disk failure with minor impact to service and zero downtime. The GFS requires fencing hardware of some kind. See http://www.jamescoyle.net/how-to/543-my-experience-with-glusterfs-performance. I must be honest, I have not tested this yet so I’d be interested to know how you get on. GlusterFS comes in two parts: The below diagram shows the high level layout of the storage set up. GlusterFS. I tried to search but dint get it. GlusterFS handles this synchronisation seamlessly in the background making sure both of the physical machines contain the same data at the same time.

I haven’t heard anything myself but it does sound interesting. This ensures that blocks which have been added to an inode will have their content synced back to disk before the metadata is updated to record the new size and thus prevents uninitialised blocks appearing in a file under node failure conditions. http://www.gluster.org/community/doc...php/QuickStart, LXer: Automatic File Replication Across Two Storage Servers (GlusterFS + Ubuntu 12.10), LXer: Automatic File Replication Across 2 Storage Servers With GlusterFS On CentOS 6.3, Can RHEL 5.3 cluster mount GFS2 filesystem.