OCFS2
The Linux SCSI Target Wiki
| Developer | Oracle Corporation |
|---|---|
| Full name | Oracle Cluster File System |
| Introduced | March 2006 (Linux 2.6.16) |
| Limits | |
| Max file size | 4 PB (OCFS2) Currently limited to 16TB since it uses the Linux JBD |
| Max filename length | 255 bytes |
| Max volume size | 4 PB (OCFS2) |
| Allowed characters in filenames | All bytes except NULL and '/' |
| Features | |
| Dates recorded | modification (mtime), attribute modification (ctime), access (atime) |
| File system permissions | Unix permissions, ACLs and arbitrary security attributes (Linux 2.6 and later) |
| Transparent compression | No |
| Transparent encryption | No |
| Data deduplication | No |
| Supported operating systems | Linux |
- See platforms for a complete overview over all supported devices and CPUs.
OCFS2 stands for Oracle Cluster File System (version 2). It is a shared disk file system developed by Oracle Corp. and released under the GNU General Public License.
The first version of OCFS was developed with the main focus to accommodate oracle database files for clustered databases. Because of that it was not an POSIX compliant file system. With version 2 the POSIX features were included.
OCFS2 (version 2) was integrated into Linux version 2.6.16 of. Initially, it was marked as "experimental" (Alpha-test) code. This restriction was removed in Linux version 2.6.19. With kernel version 2.6.29 more features have been included into OCFS2 especially access control lists and quota.[1]
OCFS2 uses a distributed lock manager which resembles the OpenVMS DLM but is much simpler.[2]
Contents |
Prototype
An OCFS2 on iSCSI prototype is up and running (over WLANs).
The OCFS2 modules and ocfs2-tools package are running on OS-2008 r51-3 (2.6.21-omap1) on a Nokia N800. The current prototype is connected to a two node cluster, with the 2nd Initiator being a Ubuntu 7.10 i386 VM running 2.6.21 with Open/iSCSI. The iSCSI target storage for the prototype is provided from a PS3 running LIO Target+iSCSI on Linux 2.6.25.
Version info
Nokia-N800-51-3:/# dmesg | grep OCFS [ 118.765625] OCFS2 Node Manager 1.3.3 [ 118.875000] OCFS2 DLM 1.3.3 [ 118.929687] OCFS2 DLMFS 1.3.3 [ 118.945312] OCFS2 User DLM kernel interface loaded [ 119.117187] OCFS2 1.3.3
o2cb Status
Nokia-N800-51-3:/# /etc/init.d/o2cb status Module "configfs": Loaded Filesystem "configfs": Mounted Module "ocfs2_nodemanager": Loaded Module "ocfs2_dlm": Loaded Module "ocfs2_dlmfs": Loaded Filesystem "ocfs2_dlmfs": Mounted Checking O2CB cluster ocfs2: Online Heartbeat dead threshold = 15 Network idle timeout: 10000 Network keepalive delay: 5000 Network reconnect delay: 2000 Checking O2CB heartbeat: Active
mounted.ocfs2
Nokia-N800-51-3:/# mounted.ocfs2 -f Device FS Nodes /dev/sdb ocfs2 Nokia-N800-51-3, ubuntu_initiator
/proc/mounts
Nokia-N800-51-3:/# cat /proc/mounts | tail -n 4 /dev/sda /iqn.2003-01.org.linux-iscsi.playstation3.cell:sn.73b073c4e157/PS3_FILEIO ext3 ro,data=ordered 0 0 configfs /sys/kernel/config configfs rw 0 0 ocfs2_dlmfs /dlm ocfs2_dlmfs rw 0 0 /dev/sdb /iqn.2003-01.org.linux-iscsi.playstation3.cell:sn.73b073c4e157/PS3_OCFS2 ocfs2 ro 0 0
lsmod
Nokia-N800-51-3:/# lsmod Module Size Used by ocfs2 359764 1 - Live 0xbf132000 ocfs2_dlmfs 18792 1 - Live 0xbf12c000 ocfs2_dlm 178472 2 ocfs2,ocfs2_dlmfs, Live 0xbf0ff000 ocfs2_nodemanager 125260 7 ocfs2,ocfs2_dlmfs,ocfs2_dlm, Live 0xbf0df000 configfs 23280 2 ocfs2_nodemanager, Live 0xbf0d8000 iscsi_initiator_mod 277956 3 - Live 0xbf093000 ext2 51080 0 - Live 0xbf085000 ext3 107304 1 - Live 0xbf069000 mbcache 7108 2 ext2,ext3, Live 0xbf066000 jbd 51592 2 ocfs2,ext3, Live 0xbf058000 g_file_storage 27560 0 - Live 0xbf050000 cx3110x 56200 0 - Live 0xbf041000 umac 258788 1 cx3110x, Live 0xbf000000 (P)
Initiator
Nokia-N800-51-3:/# /etc/init.d/initiator status | tail -n 5 Core-iSCSI Initiator Stack v1.6.2.10 on Linux/armv6l on 2.6.21-omap1 iSCSI InitiatorName: iqn.2003-01.org.linux-iscsi.Nokia-N800-51-3.armv6l:sn.506dcc5299c Linux Nokia-N800-51-3 2.6.21-omap1 #2 Fri Dec 7 11:17:13 EET 2007 armv6l unknown 13:35:59 up 13:15, load average: 0.42, 0.34, 0.34
Download
- iSCSI/Meamo/OS-2008/OCFS2 (archive)
- Dependencies: The required userspace debs are ocfs2-tools, libcomerr2, and bash3 and are also in LIO-Cluster above.
Build
Untar ocfs2-2.6.21-omap1.tar to your /media/mmc2 directory, which should create /media/mmc/ocfs2/ for the OCFS2 kernel modules.
See also
Notes
External links
- OCFS2 Official website
- OCFS2 Wikipedia entry
- Clustered file system Wikipedia entry
- Shared disk file system Wikipedia entry
- Oracle
