This version of this document is no longer maintained. For the latest documentation, see http://www.qnx.com/developers/docs.

fs-qnx6.so

Shared object that supports the Power-Safe filesystem (QNX Neutrino)

Syntax:

driver ... qnx6 qnx6_options... &

Runs on:

Neutrino

Options:

hold=allow|root|deny

Control which users (if any) can suspend the taking of snapshots (via a flag in the DCMD_FSYS_FILEFLAGS devctl() command). The default is root.

overalloc

Enable a block overallocation heuristic for small file writes.

snapshot=freq

Set the frequency of automatic snapshots; the default is 10 seconds. A filesystem snapshot is explicitly made when you call sync() or fsync(), or from this periodic timer.

sync=mode

Specify the required disk synchronization capability. The mode mode must be one of the following:

• mandatory (the default) -- the drive must support synchronization to allow a filesystem to be mounted read/write.
• optional -- fail any read/write mount attempt if the filesystem doesn't support synchronizing.
• ignore -- never issue a synchronize command to the disk.

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If the drive doesn't support synchronizing, fs-qnx6.so can't guarantee that the filesystem is power-safe. You can use the sync option to override this requirement at your own risk.

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Description:

The fs-qnx6.so shared object provides support for Power-Safe (copy-on-write/snapshot) filesystems. It's automatically loaded by the devb-* drivers when mounting a Power-Safe filesystem.

See also:

chkqnx6fs, devb-*, mkqnx6fs

"Power-Safe filesystem" in the Filesystems chapter of the System Architecture guide

"Power-Safe filesystem" in the Filesystems chapter of the Neutrino User's Guide