Troubleshooting Mac OS X 10.3.x: Sparse disk image data loss; VPN issues; Bluetooth menu issues
Sparse disk image data loss? A MacFixIt reader reports a reproducible issue where leaving a sparse disk image mounted when you restart can result in the loss of data on the disk image:
"A Specific situation causes data corruption inside sparse disk images. Recently created, modified, or copied files inside a sparse disk image will become corrupted if the disk image is not unmounted before rebooting. Upon restart, opening the disk image and examining the files shows that they retain their sizes but are filled with null bytes.
"To recreate the problem:
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1. Create a 100Mb sparse disk image saved to the Desktop.
2. Copy approx 50Mb of files to the image.
3. Create a text file at the root of the image with some text in it.
4. Leave the image mounted.
5. Restart the machine.
6. Open the Disk Image and the open the text file.
7. It will be filled with null bytes, as are most or all of the other files that were copied.
"This problem has been nagging me for a long time, and I finally realized that the problem occurred after restarts. I installed a clean copy of 10.3.0 and updated it to 10.3.1 and then followed the steps above to recreate the problem. Repeated this several times and tested regular disk images as well. They did not corrupt the data, but the sparse images did. If I unmounted the disk image before rebooting, the data would be fine."
We have not yet verified the above procedure/data loss.
Problems with Cisco VPN (L2TP) Although Mac OS X has supported virtual private networking (VPN) using the Point-to-Point Tunneling Protocol (PPTP) since OS X 10.2, one highly-touted feature of Panther is support for Layer 2 Tunneling Protocol (L2TP) from within the Internet Connect utility. However, we've received a number of reports from readers who haven't had any success connecting to Cisco VPN servers using L2TP. A thread on Apple's Discussions forums is representative, with users reporting that they can connect using Cisco's own OS X client, but not using the built-in client (via Internet Connect).
Bluetooth menu disappears? MacFixIt reader Leor Bleier reports odd behavior with the Bluetooth status menu under OS X 10.3.x:
"I wanted to report a problem I have noticed with OS X 10.3.x. If the Bluetooth menu is in the menu bar and I turn Bluetooth on, the moment I send something to the Mac (PB 12") from my phone (Sony Ericsson T616), the menu icon disappears. Bluetooth is still on, but for some reason the 'Show Bluetooth status in the menu bar' gets unchecked. I have to manually go to System Prefs and re-select it. Has anyone else reported such behavior?
Panther problems? Drop us an email at Late-breakers@macfixit.com.
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Ditto.
It's one of the formats of disk image Panther's Disk Utility can create. If you make a new blank image, it's one of the options in the popup. Basically, it's a disk image that only takes up as much space as it needs--it will grow as you add stuff to it, unlike the old images which always took up the full space allotted to them.
You could create them with the terminal before, but Panther's Disk Utility can make them now. I assume they're something like the format that File Vault uses, too.
MacOSXHints has an old but interesting tip on them:
http://www.macosxhints.com/article.php?story=20030212055706937
Apparently, they're prone to corruption after an "unclean" restart...
They're also suspected as a prime culprit in the FileVault data loss issue.
This may be another symptom of the same problem.
Although sparseimages are involved in File Vault, I get the feeling that at least the main File Valut problem was somewhat different.
The problem (pre 10.3.1, anyway) that most people were having with File Vault occurred when trying to reclaim unused space. Assuming File Vault uses sparseimages, that would be a different situation; sparseimages grow to accomodate the amount of data in them, but don't shrink if you delete things. Hence, no freeing up deleted space in File Vault. Whatever algorithm Apple was using to make that space available was apparently failing under 10.3.0.
Sounds somewhat different to me, although you never know.
NULLS get written to the device upon shutdown if its mounted. Sounds
like the FW bug may just be a general problem with non-local (ie inside
the machine) disks, period.
Indeed; the resemblance is creepy. Maybe the phantom FW400 dataloss bug that Apple denies but people insist keeps happening hasn't been a firewire bug at all, but an issue with mounted ANYTHING on restart, and FW drives are just prone to it for whatever reason.
That'd certainly explain why Apple and Oxford keep insisting there's nothing wrong with FW400. If that is the case, I sure hope Apple fixes whatever IS the problem.
- by Mark Lewis--2008 December 3, 2003 8:02 AM PST
- I tried the procedure twice. There was no data loss in the text file.
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