mount.ocfs2(8)

✨ mount.ocfs2 ✨ — like, the OCFS2 manual page, bestie edition 💖

okay so you're here for mount.ocfs2(8), the section-8 manual page for mounting an OCFS2 filesystem. pull up a chair, grab a strawberry 🍓, and let's get you fluent. no cap, it's all here.

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🌸 NAME 🌸

mount.ocfs2 — mount an OCFS2 filesystem

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🦋 SYNOPSIS 🦋

mount.ocfs2 [-vn] [-o options] device dir

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💅 DESCRIPTION 💅

So basically, mount.ocfs2 mounts an OCFS2 filesystem at dir. It's usually not even you calling it directly — it gets invoked indirectly by the mount(8) command. it's giving backstage crew, doing the real work while mount gets all the credit. 👑

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✨ OPTIONS ✨

okay this is the main character section, let's go one by one, no skips:

• _netdev — says that the filesystem lives on a device that needs network access. the whole point is to stop the system from trying to mount these filesystems before the network is even up. mount.ocfs2(8) transparently appends this option during mount — sneaky, but helpful. however (and this is the tea ☕) if you're mounting the volume via /etc/fstab, you have to explicitly specify this mount option yourself, so the system waits until after the network is enabled before it mounts the volume.
• noatime — the filesystem will not update access time. atime? never heard of her. 💀
• relatime — the filesystem only updates atime if the on-disk atime is older than mtime or ctime. this is the default mode. lowkey the chill one.
• strictatime,atime_quantum=nrsec — the filesystem will always do atime updates, but the minimum update interval is set by atime_quantum, which defaults to 60 secs. set it to zero to always update atime. these two options need to work together, they're a package deal 🫶
• [no]acl — enables / disables POSIX ACLs (access control lists) support. it's enabled by default.
• [no]user_xattr — enables / disables extended user attributes. it's enabled by default.
• commit=nrsec — sync all data and metadata every nrsec seconds. the default value is 5 seconds. zero means default. slay.
• data=[ordered|writeback] — specifies the handling of file data during metadata journalling. two flavours:
  • ordered — this is the default mode. data is flushed to disk before the corresponding meta-data is committed to the journal. safe and tidy, we love her.
  • writeback — data ordering is not preserved — data may be flushed to disk after the corresponding meta-data is committed to the journal. this is rumored to be the higher-throughput option. while it guarantees internal file system integrity, it can allow old data to appear in files after a crash and journal recovery. 👀 so like, fast but chaotic.
• errors=[remount-ro|errors=panic|errors=continue] — specifies the behavior when an on-disk corruption is encountered. the drama options:
  • remount-ro — this is the default mode. the file system is remounted read-only.
  • panic — the system is halted via panic. it's giving "we die together" 😭
  • continue — ignore errors. just log error message, return error code to the calling process and continue.
• localflocks — this disables cluster-aware flock(2). local vibes only.
• coherency=[full|coherency] — specifies the extent of coherency for the cached file data across the cluster. this mount option works with Linux kernel 2.6.37 and later.
  • full — this is the default mode. the file system ensures the cached file data is coherent across the cluster for all IO modes.
  • buffered — the file system only ensures the cached file data coherency for buffered mode IOs. it does not perform IO serialization for direct IOs. this allows multiple nodes to perform concurrent direct IOs to the same file. this is the recommended mode for volumes hosting database files. database besties, this one's for you 🔥
• resv_level=level — specifies the level of allocation reservation for files. the higher the value, the more aggressive it is. valid values are between 0 (reservation off) to 8 (maximum space for reservation). it defaults to 2. this mount option works with Linux kernel 2.6.35 and later.
• dir_resv_level=level — by default, directory reservation scales with file reservation. users should rarely need to change this value. if the file allocation reservation is turned off, this option will have no effect. this mount option works with Linux kernel 2.6.35 and later.
• inode64 — indicates that the file system can create inodes at any location in the volume, including those which will result in inode numbers greater than 4 billion. big numbers, big energy. 🔢
• nocluster — this option allows users to mount a clustered volume without configuring the cluster stack.

okay so ⚠️ you must be aware that you can only mount the file system from one node at the same time — otherwise the file system may be damaged. please use it with caution. fr fr, be careful.

• [no]intr — specifies whether a signal can interrupt IOs. it is disabled by default.
• ro — mount the file system read-only. look, don't touch. 🙈
• rw — mount the file system read-write. touch away. 💖

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🎀 NOTES 🎀

to mount and umount a OCFS2 volume, do:

# mount /dev/sda1 /mount/path
 ...
# umount /mount/path

users mounting a clustered volume should be aware of the following:

1. the cluster stack must to be online for a clustered mount to succeed.
2. the clustered mount operation is not instantaneous — it must wait for the node to join the DLM domain.
3. likewise, clustered umount is also not instantaneous — it involves migrating all mastered lock-resources to the other nodes in the cluster.

if the mount fails, detailed errors can be found via dmesg(8). these might include incorrect cluster configuration (say, a missing node or incorrect IP address) or a firewall interfering with o2cb network traffic. check the configuration as listed in o2cb(7) or the man page of the active cluster stack. it's always the firewall, bestie. 🧱

to auto-mount volumes on startup, the file system tools include an ocfs2 init service. this runs after the o2cb init service has started the cluster. the ocfs2 init service mounts all OCFS2 volumes listed in /etc/fstab.

# chkconfig --add o2cb
o2cb 0:off 1:off 2:on 3:on 4:off 5:on 6:off

$ chkconfig --add ocfs2
o2cb 0:off 1:off 2:on 3:on 4:off 5:on 6:off

$ cat /etc/fstab
 ...
/dev/sda1     /u01     ocfs2     _netdev,defaults     0  0
 ...

(yes, the output line under chkconfig --add ocfs2 says o2cb in the original — not me, I'm just the messenger 💀 keeping it exactly as written.)

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🌈 SEE ALSO 🌈

debugfs.ocfs2(8) fsck.ocfs2(8) mkfs.ocfs2(8) mounted.ocfs2(8) o2cb(7) o2cluster(8) o2image(8) o2info(1) tunefs.ocfs2(8)

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👑 AUTHORS 👑

Oracle Corporation

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💜 COPYRIGHT 💜

Copyright © 2004, 2012 Oracle. All rights reserved.

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and that's the whole page, bestie — you ate it. 🫶✨

this was Version 1.8.9, dated January 2012, and it's mount.ocfs2(8) from the OCFS2 Manual Pages — go forth and mount responsibly, ily, bye 💅🌸