View Full Version : Disk errors repoted using SD yet Disk Utility works fine.

08-21-2005, 06:19 PM
Twice I've tried to use SD to clone a drive (Tiger) to an external firewire drive and it never finishes. The external drive is a 200GB drive partitioned into 2 volumes. There are no errors listed in the SD log but the System Log lists several errors:

Aug 20 03:51:58 MyMac cp: error processing extended attributes: Operation not permitted
Aug 20 07:54:09 MyMac kernel[0]: disk2s10: I/O error.

The last I/O error is repeated frequently (it appears to be every 30 seconds). Th last few lines of the SD log are:

|04:23:31 AM|Info| Ignoring /private/var/tmp/4306327709b1f
|04:23:31 AM|Info| Ignoring /private/var/tmp/42ef72d35918c
|04:23:31 AM|Info| Ignoring /private/var/run

Eventually I stopped the backup.

The System Log shows no such I/O errors with the external drive yet when I use Disk Utility to clone the drive (using Restore) and it backups up with no errors listed in the System Log (during the backup the system went to sleep but as soon as I woke it up the backup finished; odd that it would sleep during disk activity). The DU log says the backup was successful.

I have run TechTool and Disk Warrior against the external drive and they report no errors.

I have run the backup twice with SD and each time I/O errors are listed in the System Log but a backup using DU appears to work fine.

So now I don't know if SD has a problem or Disk Utility (or the OS) is failing to report an error and the backup wasn't really successful (that would be scary).

Any thoughts why the reported Disk Errors in SD


P.S. > this probably has nothing to do with it but I using a PowerMac G4 AGP. The ATA controller is the older version can only access 128MB (or whatever the number is) whereas the external FW drive has a newer ATA bridge so it can handle my larger 200GB drive (that was partitioned into two smaller drives)

08-21-2005, 06:48 PM
Is the external drive disk2s10 according to System Profiler, Steve?

08-21-2005, 09:34 PM
Hi Dave,

That's correct. The Sytem Profile lists it as the external drive:

FireWire Bus:

Maximum Speed: Up to 400 Mb/sec


Manufacturer: Oxford Semiconductor Ltd.
Model: 0x1
GUID: 0x1D200E0890047
Maximum Speed: Up to 400 Mb/sec
Connection Speed: Up to 400 Mb/sec
OXFORD IDE Device LUN 0 Unit:
Unit Software Version: 0x10483
Unit Spec ID: 0x609E
Firmware Revision: 0x138
Product Revision Level: 08.0
Capacity: 186.31 GB
Removable Media: Yes
BSD Name: disk2
OS9 Drivers: Yes
S.M.A.R.T. status: Not Supported
Backup HD 1:
Capacity: 111.77 GB
Available: 11.11 GB
Writable: Yes
File System: Journaled HFS+
BSD Name: disk2s10
Mount Point: /Volumes/Backup HD 1

08-21-2005, 10:04 PM
Ok: what I'd suggest is using Disk Utility to erase and zero the external drive: both the data and free space. I think you really are getting I/O errors on the drive, and this is the best way to at least remap any bad sectors.

I know that things were working in DU, but that copies entirely differently. The errors are being returned from the kernel, though, so I really do think they're real errors!

08-21-2005, 10:58 PM
Thanks. Dave I'll give that a shot. I supose it's also possible the kernal has a problem with firewire drives that isn't exposed using DU. It wouldn't be the first time OS X had firewire related problems.

08-22-2005, 08:02 AM
It's also possible that, during low-level block copying operations (which is typically what DU does), errors are being dealt with entirely differently -- it might be remapping itself. Really hard to say since we don't have the code... but, the kernel is clearly indicating problems, and that's almost always due to surface or communication errors.