does anyone know if the Unix File System (ufs) is a journaling file system? If I were to format my partition as UFS, would I be able to have journaling capabilites under OSX, since HFS+ does not support it?
UFS is not a journaling file system, but there are journaling file systems that unix OS's can use. The Riser FS is one example for Linux. There are others. I don't believe that there are any that OSX can run on.
I've been reading a lot about MacOS X and one thing that I keep reading is that its structure makes it file system independent... so I suppose that is a matter of porting XFS (Silicon Graphics Open Source offering), JFS (IBM's) or RiserFS (Linux variant).
There some really good commercial offerings like Veritas (the one used in AT&T Unix System V Relase 4.2), but I don't think Veritas will port it to MacOS X.
Riser for OSX would be nice. If Oracle ports to OSX (8i anyone?) it could be really improtant to have a journaling FS, otheriwise, I don't know how important it really is. Personally I would rather have them do better documentation on the development methods and tools.
I'm a little frustrated that Apple so far has not chosen to implement a Journaled file system. I've used unix box's with and without journaling and not having it can be very painful(Hours of fsck's). I'll bet though Veritas will enter into the mix and offer up their JFS product after the initial offing. Presently Veritas behind the scenes provides the Journaling for other OS's, HP-UX and Win2k to name a couple. Hopefully Apple will, or someone will come up with one for us.
I might be a little naive but...why have such a discussion about UFS when OS X can use HFS+ ? I will admit that I hvae no idea what a journaling file system is, and maybe some kind sould can clue me in, but for continuance sake I will keep using HFS when OS X rolls out
If you want a plain answer here is my translation:
A Journaling File System is a file system that won't lose data in case of a crash because it has mechanisms to store in real time. This is very important in high availability enviroments (critical applications that can not permit a corruption and loss of data) like nuclear, medical, etc... applications.
The discussion was not really about UFS or HFS+, but the necesity/convenience of a journaling file system... and not UFS nor HFS+ are jfs file systems.
If Apple wants to enter the enterprise business they need to have the options of a jfs.
The real advantage to a journaling file system (like the one IBM has had on it's AIX boxes for the past few years) has to do with recovery time when a file system crashes or is not synced properly before reboot.
Some systems with large amounts of data (say, storing an Oracle Database for example) can take hours to run the UNIX "fsck" which is sort of like, but not quite, the equivalent of a DOS chkdsk /f - if there's many gigabytes of data involved this can take hours and hours - especially if you have multiple disks on your system. You may notice that MacOS X will sometimes complain about "dirty" file systems when rebooting after a crash......and this is the same thing, the file system was not unmounted cleanly.
A journaling file system keeps records of what it has and has not written to the disk, and therefor, if a crash or system failure occurs, the O/S need only check what's in the journal to see which writes have been comitted to the disk...it's not necessary to check the whole disk.