Disk fragment

If I copy a dvd movie to my hard drive and then delete it will that leave a 7 GB fragment on my disk or will my files fill the space in.

It will leave 7 GB of free space which will be used when it is needed, In other words, other larger sectors will be used first. But there's really little reason to think about it.
-mj

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Disk Fragmentation

Given the very nature of OS-X, to what extent should disk fragmentation be of concern? Is it worth investing in a disk defrag utility?
Thanks -
Lyman

No. OS X automatically defrags all files less than 20 MB in size on the fly. Plus the fact that modern hard drives are very fast means defragmentation is not really needed. The following article should be helpful reading: Fragmentation in HFS Plus Volumes.

Osx desktop vs osx server disk fragmentation?

does anyone know if 10.5 server is any different than 10.5 desktop regarding disk fragmentation? if server is any better then desktop at minimizing fragmentation, i might just go there...
thanks-

while i never rule out the possibility of hardware problems, in my experiences, hard disk failures have generally had similar symptoms... the symptoms tend to be cyclic retrys for reading, i can here the retries, and the computer has interrupted responsiveness... another type of symptom i've seen with disks that are failing is corrupted files (usually unreadable with a disk error message, reading or writing) poping up... the disks where i've had fragmentation issues, it has always been long continuous reads, but the computer doesn't have any halting in responsiveness... it's mostly slugishness when accessing large files, like starting programs...
although i don't rule out the possibility of a disk problem, the symptoms are matching the later case at the moment... of course, when i eventually try something to address fragmetnation, that should help either eliminate the problem or rule out fragmentation and suggest the latent hardware problem... like the saying goes, there are 2 kinds of hard drives, those that have failed and those that are going to fail...
regarding the suns, they were servers and ran software as well... we had x-windows terminals as well as macs and windoz computers running software on the suns (mostly thru x-windows)... they also were nfs servers for our sun workstations on peoples desks... although we didn't have the bloatware that is ubiquitous these days, we had a fair amout of large simulation software for finite element analysis, circuit simulation like pspice, database software, etc... some people wrote and compiled software on them... they were also our mail servers and our gateways to the rest of the network... i seem to recall framemaker in the mix for a brief time... (not sure what ever happened to that company...) we had 3 servers and about 130 to 140 people in my working area. yes, many of those people were doing lesser activities like email and not running simulation software... but it is still nothing to sneeze at...
although this was toward the start of "the web" much of what is done on computers today had already existed before that... it was just not well known... before there was "chat", unix had "talk"... i've had an "internet" based email since 1985... there were image viewers... i recall seeing the 1st streaming mpegs sometime in the early 90's. of course the internet did not have the bandwith so the streaming mpeg was very slow... but i digress...
one of the most intersting developments i thought was really hypercard on the mac... it was the prototype for the web... it had graphics, scripting, networking access for transfering and displaying information, rudimentary animation, etc.... if it had been multiplatform and an open protocol instead of apple only, that might have been the model for the web... well, i've digressed again...
regarding disk fragmentation, the basic unix partitioning scheme really reduces the disk fragementation issue... that is to format with 3 partitions, 1 for the OS, 1 for the user files, and most importantly 1 for /var for all the temp files that get created and swap space for virtual memory... since the files which come and go and change size a lot are on the /var partition any fragementation from those would be restriced to that partition... since it is changing of files that causes the fragmentation, the temp files which change more freqently often drive the fragementation issue... the occasional reboots tend to clear out the temp files in /var... so with this scheme, the majority of the fragmentation is limited to /var, which is cleared and much of fragmentation isn't normally persisant across reboots...
at least that is my experience... i recognize that others may have different opinions or experiences... thanks for the trip down memory lane... i miss the days when there were standards for how the internet worked before microsoft arrived on the internet and made all these competing non-standard protocols... but that is another topic...

What about Scratch Disk fragmentation?

I edit TIFF image files with lots of layers that range in size from 50MB to 90MB. With only 4GB of RAM, my system relies heavily on scratch disk performance for these large files. I have a non-system internal SATA HDD with an 80GB volume dedicated as a scratch disk.
I have read that it's important the scratch disk be a defragmented volume. I have also heard that Macs defragment files smaller than 20MB automatically, which I don't think helps me much.
My questions are, does Photoshop CS4 delete/remove files on the scratch disk after an edit session ends and PS is closed, and then starts with a "clean slate" when re-opened? Or do all the scratch disk files just pile up in pieces over time that tend to fragment the scratch disk? If so, does the scratch disk need to be re-formatted (erased) regularly? Thanks.

Marian Driscoll wrote:
If there is nothing on that 80GB volume (when Photoshop is closed) then there is nothing to worry about. Fragmentation is only an issue if the drive has files on it.
Thanks Chris and Marian.
I have been monitoring my scratch disk in Disk Utility and have noticed that after closing PS, the amount of disk space indicated as being used drops from about 1GB to around 60MB, with the number of files indicated on the disk dropping to around 40. When I erase the volume using D.U., then there are 32 files indicated as being on the volume.
So apparently, there are files being created by both the OS (around 32 files) and also PS (around 8) that remain on the scratch disk after PS is closed. Maybe these PS files are just "place-holder" files, because the amount of space used by these PS files appears to be less than 1MB. Relative to an 80GB volume, this seems rather insignificant.
Nevertheless, I'm now thinking that it may be a good maintenance practice to erase (re-format) my scratch disk once a month or so just to help optimize it. It's easy to do in Disk Utility.

Disk fragmentation problem

I noticed some applications are fast and others slow. I suspected fragmentation because I had been running with an almost full disk for some time. I have now deleted some large home movie files. I then ran IDefrag which tells me the disk is badly fragmented.
So using Disk Utility and my firewire drive I erased a partition of the firewire drive did a restore to the firewire drive and can now boot off the firewire drive. I then ran IDefrag on the firewire drive and it gives me the same fragmentation pattern and files - I had expected it to have no fragmentation.
I was hoping to be able to erase my computer's hard drive and then restore from the firewire drive and have no fragmentation, but if the firewire drive has the same fragmetation, this will leave me no better off.
How do I get it restored to my drive with no fragementation? I have plenty of space on the external drive.
(BTW running IDefrag resulted in IDefrag hanging for hours and not progressing and showing up red in Force Quit, so it did not solve the issue - I placed a support call with them)

Hi Paul, download Carbon Copy Cloner. Wipe your internal HDD and clone back. If iDefrag finds any fragmentation trash it
-mj
[email protected]

How do you fix imac disk defragmentation? I used Drive Genius 3 and the same things keep coming back as fragmented.

How do you repair disk defragmentation on an imac? I tried with Drive Genius 3 and after completion the same defrag keeps showing up.

Disk fragmentation and particularly whether it can be fixed, is very controversial. The following thread is worth reading:
https://discussions.apple.com/thread/3327627?start=0&tstart=0
I think it's true that disks can become fragmented, and this can affect performance. However it is also said that the OS X file system attempts to address this issue in the background all the time, apparently for certain sizes of files in particular.
In my experience the biggest problem is actually lack of disk space. If you don't have a fair amount of free space on your drive, tinkering with the fragments won't help much if your system needs to create a swap file or do some other maintenance. So my recommendation is that you follow the advice to clone and re-create your drive, but if you have limited free space, consider upgrading the disk or the entire computer in the longer term.
Hope that's helpful.
Ivan

CoreAudio: Disk is too slow

Have just switched over to MAC Pro Intel, a few years old. When press play in Garageband 3 get message "CoreAudio: Disk is too slow. (Prepare) (-10001)" This applies all previous Garageband 3 files and any newly created ones. I cannot play any of them. Can you tell me what this means and how I can fix? Thanks.

I looked at the Activity Monitor and didn't see anything using up resources. I saw disk writes peak out, but nothing to suggest why. I recorded track after track in the same project and finally after the 4th track, it started recording as long as I wanted without a problem. I'm going to chalk it up to disk fragmentation in that particular area.

Backup to Disk Performance

Hello Everyone,
We are currently using Backup Exec for Windows 11D to perform an online backup of our 4.6C system to tape. Since we are moving towards a 24x7 operation, we purchased a new server and storage array with hopes of achieving better transfer rates backing up to disk rather than tape.
Our technical details are as follows:
SAP R/3 4.6C server:
HP380
Windows 2003 Enterprise SP2 32-bit
Oracle 10.2.0.2
Db 320 gb
Backup Exec Server:
HP380 G5 64-bit
Backup Exec for Windows 11d with R/3 agent 64-bit
Latest BE build and hotfixes applied
Windows 2003 Enterprise SP2 64-bit
Target drive for backup files:
HP MSA60 Storageworks array
12- 750gb SATA drives in a raid 6 configuration
Our tests have been frustrating and disappointing. To our super dlt tape drive we are able to backup our 330 gb system at approximately 2,500 mb/minute or about 150 gb an hour. To disk, we are getting anywhere from 250 mb/minute to 1,350 mb/minute...half speed at best or much, much worse What seems to happen is that the disk backup will start running at near tape speed. But the longer the backup goes, the slower the backup becomes.
I have tried pre-allocating the .bkf files ahead of time. To pre- create a 100 gb .bkf it takes about 2 hours while the backup idles until the file creation is complete. While not an ideal runtime, I can live with it if the backup would run faster than tape once the file is created. But always the "same slowdown as it goes" seems to occur. When I don't pre-allocate the files and allow the file to grow as the backup runs, the backup will inevitibly hang or crawl at less than a couple of hundred mb/minute.
I'm sure that disk fragmentation is adversely affecting us. But even after we defrag the drives the same thing will occur.
We have a ticket open with Symantec but so far they have not been of much help.
Is anybody using Backup Exec for Windows to backup their SAP on Oracle system to disk? And what db size and backup speed are you achieving? Are there certain settings you find that will improve the backup speed? Any feedback would be greatly appreciated.
Thank you in advance,
Rich

Hi!
I see at least two possible reasons:
1. Is a virus scanner running on your Backup Server?
2. Has the network interface from R/3 to the disks enough bandwidth?
Hope this helps.
Regards,
Volker

Quicktime 10 (or HDD) slow after TM restore, HDD fragmentation?

Hi there,
have a rather weird problem with Quicktime 10. I am producing timelapse videos on a QuadCore iMac and it always has been fast and smooth (and some files - prior to further postprocessing - can be rather big > 2-4 GB).
recently I had to restore the machine from a TM backup.
now, if I - since that restore - watch the bigger timelapse videos (mark file in finder and hit space key) they are not displayed smooth, but "hang" in between, or jump frames for seconds.
the harddisk (450 GB remaining free) seems to start heavily working (can see it in the system monitor).
as I was curious I just copied some of the same GB vids to my dualcore macbook pro, and there they can be displayd smoothly.
may it be that some disk fragmentation has happened via restore? I thought that OSX has no fragmentation?
any ideas?
thx
chris

I have to add that it is also happening in QT 7 that Videos are choppy and I does not change when I put a video on a firewire or external disk. Again, this was not the case before the TimeMachine restore.

Mounting disks/partitioning. Alternatives to fstab?

I wanted to be able to separate the OS, Applications and Users and had found an excellent article by Justin (Ref: http://www.macosxhints.com/article.php?story=20040716153639236). But now with Snow Leopard, fstab has been discontinued and this won't work
Is there any alternate solution to achieve the same as I would want to
1. Install OS in a separate partition
2. Put swap in separate partition (this is still doable but here I'm not looking for pro's con's of doing this)
* the above two would significantly help reduce disk fragmentation I suppose as the main reason for me to do this is, once the disk is near full, performance goes for a toss and getting tired of seeing rainbow circles
3. Put the /Applications in a different partition (may be on the same disk as root)
4. Put /Users on to second disk
Looking for some pointers as well as some insight into how the partitions are handled in Snow Leopard.
Thanks in advance,
-Kesari.

Thanks to every one of you who helped me with the answer. In particular KJK555's comment wrt fstab as well as pointers suggested by R C-R. It was a good reading and indeed a good learning experience for me as this provided quite a bit of insight into Mac for coming from Solaris/Linux. Also, my boot time is under 36 secs with all my apps, initialization with toshiba 500gb 7200rpm disk (would scream if I could get a ssd I suppose. But with mbp, have to live with one disk unless I forego my dvd drive).
Now, to answer why I did this or rather why I wanted to do this extra (unwanted ?) steps:
I can't religiously monitor my disk usage and putting all under one partition, install, uninstall applications etc and I would figure out that either /tmp run out of space or system crash and take for ever to reboot and then end up finding what I can part with and where to squeeze in space from
Now at least by keeping root partion out of all these hassle, I'm safe as I won't run out of space in /.
Another immediate benefit I could think of is, I don't need regular backup of most of the partitions and take only selective ones. In particular of some one is using vmware or virtualbox and set up timemachine, they would love to have this as only they know the pain. Now it's simple. Just put all the vm's in one partition and setup snapshot from the vm onto another partition and take the initial backup of the vm's partition and just setup time machine for the snapshot area. I could go on with advantages but would leave it for other's imagination. Video editing folks !!!
Coming to mistakes or rather my learning experience.
The suggestions in macosxhints works very much except for the fstab changes and here's some tips for those who's looking for this info:
1. The mounting order is always not the same i.e. don't expect /dev/disk0s3 to be mounted as /whatever. This never works. Mount using the UUID instead.
2. Do not try to mount / from fstab and just leave it to the OS. For that matter, just mount those you need it different and leave the rest (in my case now it's only Applications and Users)
3. Trying to add swap or moving it around to a different partition is waste of time as I didn't find any significant gain by doing this. Rather I think by doing this you will be limiting the swap size to the partition size. Now that / is good enough (40gb is quite a lot once you move /Applications out) and this gives excellent leg space for swap or any files in /
4. Not sure but I think this is due to the way OS initializes/uses Applications folder. When I tried to put Applications on to a different disk, it doesn't seem to like it and felt boot time was more as well as login/initialization time. But works fine after boot. Don't think this is a stopper as I have plenty of space to put in Applications on the first drive containing root.
Now I'm going to reinstall (3rd attempt) as with this experiment, found that I may not need such a huge root and (redundant) swap partitions. Little more to my /Users. Here's my planned allocation: root 20gb, alternate root 20gb (for future use), Applications 120gb, Users 120gb, data 200gb.
Once again thanks to all of you for this information.
Wouldn't it be slick, if Apple would produce a 4 or six core Developer's edition MacBook Pro with
up to 16GB of ram and one of WD's new 600GB 10,000 rpm 2.5 inch Velociraptor as standard
equipment?
This would be my dream MBP and would be the first one to buy if it's under $1500

Disk defragmenter for 10.4.6 please help

im running 10.4.6 and it seems like my drive is fragmented by the way its running and looking for files anyone know any programs that support 10.4.6 last time i used tech tool pro and lost my partitions so im looking for something that is compatible to defragment 10.4.6

Hi Ezequiel
Generally, in OS X, disk fragmentation is not the cause of slow file access.
I would first recommend a few simple checks and tests:
How much disk space do you have free on your drive?
Have you rebooted from your install CD, run Disk Utility and Repair Disk?
You might want to look into these options:
- Buy a second internal hard drive, and use a duplication tool such as Carbon Copy Cloner to make an exact copy of your system to it (which will be "defragmented"). Switch your startup disk to the second drive and use the first as a spare
- Buy DiskWarrior and optimise your directory (the file which controls all read/write access to files on your drive). This is an excellent disk troubleshooting tool in any event.
Matt
2.5GHz|3.5GB G5, 1.5GHz|512MB PB12, iSight, 4G iPod Mac OS X (10.4.5)

Hard disk life with frequent data write and read

Dear All,
Can you kindly advise on the effect of frequent write / read on shortening of (ordinary low-cost, 80 to 250G, office desktop PC type) hard disk life.
File size is IMAQ iamge file (300k byte)
1000 wite / read per day for 1 day in a week (6 days low activity, 1 day busy)

I'm going to go out on a limb and say that it should be no problem, from a life time point of view, it averages to ~150 a day over a week. Of more concern will be that you will probably start having disk fragmentation issues in a fairly short period, where continuous blocks of disk space become harder to find and the data then has to be spread over numerous locations on the drive. One end result of this is increased drive activity as the heads have to be moved all over to recover a file's data. Drives these days get a pretty good workout, with people storing thousands of MP3 music file, videos, digital camera pictures. Particularly with the MP3's they will have a lot of files that get accessed frequently. The drive, depending on O/S, will also get a lot of "random" activity, particularly if you have an indexing program such as Google desktop, running. Watch the HD light on your machine for a while and you will see it start blinking like crazy every so often when apparently nothing is running. Of course if the files you are saving are critical they should be backed up regularly to some other drive or media.
P.M.
Putnam
Certified LabVIEW Developer
Senior Test Engineer
Currently using LV 6.1-LabVIEW 2012, RT8.5
LabVIEW Champion

Contiguous disk pages

Hi all,
When I write a lot of data in a file in one method call (like RandomAccessFile.write(byte[])), I suppose that the JVM (and the OS) make its best to write data on contiguous disk pages. Is-it exact ?
If yes, could you tell me if it's the same for method that extend the file without writing data (like RandomAccessFile.setLength(long)) ?
Thanks in advance
Jean

The actual file i/o is controlled by the OS; Java just "hooks" into that. So, technically, yes, the OS will try to write large files in contiguous blocks. Modifying a file, on the other hand, will really depend upon how the OS itself handles that kind of request, plus disk fragmentation.

SAP Disk Defragment Tool

Hi Everyone! Is there a built in tool that SAP has that can do disk defragment? I've searched all over the place but unable to find anything that SAP has built in or what SAP recommends. At the moment the built in Microsoft tool is not working at a level which we would like. Any advice would be appreciated! thank you!

Connie let me explain you this:
Data fragmentation in Hard Disks is produced when data in sectors are writen and after some time are deleted, then the hard disk itself whenever you try to write information in the disk it will try to fill the empty spaces it finds starting from first sectors and so on. Usually happens that a file uses more than 1 sector so if you have 3 free sectors between used sectors and you try to write a file that uses 4 sectors the electronics in the disk will fill those 3 free sectors and then the 4th sector will be writen somewhere else, this is call as disk fragmentation because the same file information is not next to each other. This is done by the disk or controller, not by SAP or Oracle.
Now we can tell that SAP has nothing to do with disk fragmentation because writing and deleting is done by hardware (with few exceptions) so you can use ANY software that you want to use for disk fragmentation. Be aware that disk fragmentations is important after thousands of hours. What is the percentage of fragmentation that you are so worry?
If you are in Windows then use the tools that comes with Windows as it is whell known that this are the best tools for defragmentation for NTFS or NTFS2.
The tool basically will move files in a way that they will be contiguous (in sectors) and it is supposed to improve performance but this is almost imperceptible so I wouldn´t worry much about this. If you want to improve performance then write here what is the problem you have and for sure you will get lots of info and answers.

Should i partition my disk?

hi!
i have a 320 Gb @ 5400rpm hard disk on my macbook, running mac OSX 10.5 and i would like to know the advantages of partitioning my disk. does my computer go faster if i make an partition for the system and application, and another partition to the rest (music, photos)?
another question; is it usefull to defrag the disk? i bumped into a 3-party software to defrag - idefrag - should i use it or it is not necessary?
cheers!

ilucena wrote:
hi!
i have a 320 Gb @ 5400rpm hard disk on my macbook, running mac OSX 10.5 and i would like to know the advantages of partitioning my disk. does my computer go faster if i make an partition for the system and application, and another partition to the rest (music, photos)?
no, if anything it will go slower when you have to move files between partitions. there is never any reason to partition the startup drive.
another question; is it usefull to defrag the disk? i bumped into a 3-party software to defrag - idefrag - should i use it or it is not necessary?
it's normally not needed. OS X does a pretty good job of it itself. disk fragmentation can only become an issue if you hard drive fills up. if you keep at least 25-30% of the hard drive space free you never need to defragment.
the only exception would be if you often deal with large files (like video). but in this case you'd probably have an external for that. OS X doesn't auto defrag files bigger than 20MB in size.
cheers!

Disk fragment

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