Recently in Filesystems Category

I decided to start using Soft Updates on my FFS partitions in OpenBSD. I'm still running version 4.4 of OpenBSD (still waiting for my CDs to arrive and for time to figure out how to do the upgrade).

According to the portion of the FAQ cited above, using soft updates on a Unix-style Fast File System improves disk performance.

You can really see it, supposedly, in disk-intensive applications such as servers, and since all I'm doing is running a desktop (and at the moment trying to compile as little as possible), I don't expect to really "feel" an improvement, though that could very well happen.

Here is the part of Kirk McKusick's explanation of soft updates that made me want to use them:

In addition to performance enhancement, soft updates can also maintain better disk consistency. By ensuring that the only inconsistencies are unclaimed blocks or inodes, soft updates can eliminate the need to run a filesystem check program after every system crash. Instead, the system is brought up immediately.

Soft updates are invoked in the /etc/fstab file that brings up the various filesystems when you boot your Unix machine. Also see the man page for mount for a little more information.

I was already going into my /etc/fstab because I wanted to put the information for mounting a USB flash drive into the file to make it easier for me to mount the drive when I have it plugged in. Now all I have to do is:

$ sudo mount usbdrive

and the drive is mounted. I chose "noauto" as an option in /etc/fstab because I don't always have the drive plugged it. If you wish to mount a drive every session that's always connected, feel free to leave noauto out of your fstab.

Here's what my /etc/fstab looks like now (with the softdep option added to all the FFS partitions):

/dev/wd0a / ffs rw,softdep 1 1
/dev/wd0h /home ffs rw,nodev,nosuid,softdep 1 2
/dev/wd0d /tmp ffs rw,nodev,nosuid,softdep 1 2
/dev/wd0g /usr ffs rw,nodev,softdep 1 2
/dev/wd0e /var ffs rw,nodev,nosuid,softdep 1 2
/dev/sd0i /home/steven/usbdrive msdos rw,noauto,noatime 0 0

Note: since the USB drive is formatted with the FAT filesystem and not OpenBSD's FFS, I can't use soft updates on it. I could reformat it as a native FFS drive, but since I'm using it with my other, non-OpenBSD machines, I need to keep it FAT.