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malique · Feb 26, 2003, 01:43 PM

Hi,

since JFS was introduced and everybody was a bit frightened to switch it on on a working system I never heard anything anymore.

I'd like to switch it on, thinking this results in higher security *somehow*.

Is there anyone with probs/experiences who can tell me more?

Is it worth the change? Also under the buggy 10.2.4? What exactly is the effort?

thanx,

raviruddarraju · Feb 26, 2003, 01:47 PM

I didn't see any difference. Nothing bad, nothing "visibly" good.

Originally posted by malique:
Hi,

since JFS was introduced and everybody was a bit frightened to switch it on on a working system I never heard anything anymore.

I'd like to switch it on, thinking this results in higher security *somehow*.

Is there anyone with probs/experiences who can tell me more?

Is it worth the change? Also under the buggy 10.2.4? What exactly is the effort?

thanx,

CatOne · Feb 26, 2003, 01:50 PM

Originally posted by malique:
Hi,

since JFS was introduced and everybody was a bit frightened to switch it on on a working system I never heard anything anymore.

I'd like to switch it on, thinking this results in higher security *somehow*.

Is there anyone with probs/experiences who can tell me more?

Is it worth the change? Also under the buggy 10.2.4? What exactly is the effort?

thanx,

It doesn't result in higher security.

It doesn't result in better data consistency (for your data).

What it does is allow the OS to more easily recover from disk inconsistencies -- say what can happen if you pull the plug when the machine is running and it has some OS data cached that hasn't been written to disk. Instead of having to run 'chkdsk' and fix errors, it can use the Journal to see what took place and recreate the state.

I don't think it's all that important on a laptop or on a home machine that is properly shutdown. If you have lots of power failures it's likely a good idea.

NeXTLoop · Feb 26, 2003, 02:12 PM

It's one of those things that can't hurt... and may help. I've been running it since the day it was introduced, and haven't had any problems.

Millennium · Feb 26, 2003, 02:25 PM

The only thing journaling does is make your system more resilient; it is not more stable, but will recover better from crashes. Your system won't be more secure or more stable. But generally speaking, it doesn't hurt.

The performance penalty is not noticeable, unless you do a lot of stuff involving the journaled drives. Photoshop scratch disks and video capture come to mind, but you can tturn off journaling on the disks you use for this.

A quick note: do not use journaling if you only have 128 megs of RAM. Otherwise, you will see a major performance penalty, because of the virtual memory subsystem. If you have 256 megs or more, however, VM isn't likely to be used frequently enough that you'll notice any problems.

KidRed · Feb 26, 2003, 02:32 PM

Wow, I should've asked about journeling in this thread. I asked in the cocktail thread which will enable it at the click of a button and was told to do a search.

So it sounds like it won't hurt much. Can you turn it off after you've turned it on? Like if I notice a slow down can I stop it?

pat++ · Feb 26, 2003, 03:13 PM

Originally posted by KidRed:

So it sounds like it won't hurt much. Can you turn it off after you've turned it on? Like if I notice a slow down can I stop it?

yes you can :

sudo diskutil enableJournal /

and then :

sudo diskutil disableJournal /

::maroma:: · Feb 26, 2003, 03:49 PM

Great info, I was wondering the same things myself.

So, can someone in the know give a brief on what Journaling actually does (ie - how it works)? Or point me to a page?

Thanks.

gorgonzola · Feb 26, 2003, 04:39 PM

Try this article on journaling. It's Linux-oriented, but explains what journaling does, gives a rundown of some other major journaling filesystems, and has some links at the bottom to other pages that might be useful.

This is a more technical USENIX paper on the same thing.

malvolio · Feb 26, 2003, 06:48 PM

I have had one personal experience of the benefits of journaling.
I have 3 partitions on my hard drive - system, data, and swap. I had the system partition journaled, but not the other two.
A power failure during a snowstorm gave me a hard crash. When I rebooted, the data partition was so damaged that it would not mount. Had to run DiskWarrior on it to repair it. But the journaled system partition suffered no ill effects.
Now I keep journaling activated on all my partitions.

gorickey · Feb 26, 2003, 06:55 PM

Originally posted by KidRed:
Wow, I should've asked about journeling in this thread. I asked in the cocktail thread which will enable it at the click of a button and was told to do a search.

You can also enable this with "one-click" using Disk Utility.

timmerk · Feb 26, 2003, 07:26 PM

Does the system actaully know how to read the journal and try to recover? Or does it just have the journal file for now, and it won't do any good untill OS X/the computer? can make use of it?

besson3c · Feb 26, 2003, 07:27 PM

gorickey:

using 10.2.4 client you can enable Journaling in Disk Utility?

gorickey · Feb 26, 2003, 07:29 PM

Originally posted by besson3c:
gorickey:

using 10.2.4 client you can enable Journaling in Disk Utility?

Not the client, sorry...I was referring to OS X Server 10.2.4

KidRed · Feb 26, 2003, 08:15 PM

Originally posted by malvolio:
I have had one personal experience of the benefits of journaling.
I have 3 partitions on my hard drive - system, data, and swap. I had the system partition journaled, but not the other two.
A power failure during a snowstorm gave me a hard crash. When I rebooted, the data partition was so damaged that it would not mount. Had to run DiskWarrior on it to repair it. But the journaled system partition suffered no ill effects.
Now I keep journaling activated on all my partitions.

Curious, how would you enable it on one partition but not the others? I have 2 drives, and 1 has 2 partitions. I enabled journaling in the terminal, is that only for my main drive? How would I do it for the second drive, say only on the first partition?

wataru · Feb 26, 2003, 08:41 PM

If you used the command mentioned in this thread, you only enabled journaling for /. To enable it for other disks, replace "/" with "/Volumes/volumename."

Note that it is not called JFS. It is HFS+ with journaling.

KidRed · Feb 26, 2003, 10:26 PM

Originally posted by wataru:
If you used the command mentioned in this thread, you only enabled journaling for /. To enable it for other disks, replace "/" with "/Volumes/volumename."

Note that it is not called JFS. It is HFS+ with journaling.

Ah cool, thanks.

I Bent My Wookiee · Feb 27, 2003, 02:43 AM

I have been using it from day one and I still get currupt disk structure and crashes. doesn't do anything good for me really.

rantweasel · Feb 27, 2003, 07:01 PM

Originally posted by I Bent My Wookiee:
I have been using it from day one and I still get currupt disk structure and crashes. doesn't do anything good for me really.

Yeah, but that's not what journaling deals with. Journaling makes it easier for fsck to see the state of the disk when recovering from an unexpected crash/power loss. It tracks the states of open files, what data is written, etc.

mathias