Q: symbolic links get corrupted by system process?

Under those circumstances, I would just assume it is bad. Those "green" drives are particularly nasty. They cause enough trouble as externals. I wouldn't use one as an internal. When it comes down to it, I don't think you can really do the kind of enclosure and drive swapping that we all used to do. Modern drives are manufactured to be so cheap and so high performance that they have all kinds of different techniques to save money, energy, and time. There is no way to tell which ones will work in which configurations. One way to tell that it doesn't work would be some really strange behaviour like corrupted symbolic links.

I have been guity of this myself. I bought one of those "green" drives for use in Time Machine, swapping it into an old enclosure. It immediately started randomly disconnecting itself with a big red error dialog on the Mac. I returned that drive for a different one that doesn't cause that disconnect error as much. Where is the problem? Drive? Enclosure? Cable? I have no idea. I just know that now I need to fix it and I can't really tell for myself which drive is going to work. I am just waiting for the price of Thunderbolt externals to come down a bit and I'll migrate over to that and shift the known, good drives down the food chain to the old non-Thunderbolt machine.

So, I don't have a definitive answer for you. I can't say that yes the green drive is causing the problem, but I sure wouldn't be surprised.

Here is my System Report from the harddrive.  This is  a 3TB WD Green drive that I installed myself. (was an upgrade from the 1TB drive I had also installed earlier). I mention this now as the previous user also used the same o similar drive (WD/Green).  Perhaps there is a trend of those of us using the same hardware?  

Hardware Overview:

  Model Name:          iMac

  Model Identifier:          iMac8,1

  Processor Name:          Intel Core 2 Duo

  Processor Speed:          3.06 GHz

  Number of Processors:          1

  Total Number of Cores:          2

  L2 Cache:          6 MB

  Memory:          4 GB

  Bus Speed:          1.07 GHz

  Boot ROM Version:          IM81.00C1.B00

  SMC Version (system):          1.30f1

Intel ICH8-M AHCI:

  Vendor:          Intel

  Product:          ICH8-M AHCI

  Link Speed:          3 Gigabit

  Negotiated Link Speed:          3 Gigabit

  Description:          AHCI Version 1.10 Supported

WDC WD30EZRX-00MMMB0:

  Capacity:          3 TB (3,000,592,982,016 bytes)

  Model:          WDC WD30EZRX-00MMMB0                   

  Revision:          80.00A80

  Serial Number:               WD-WMAWZ0081750

  Native Command Queuing:          Yes

  Queue Depth:          32

  Removable Media:          No

  Detachable Drive:          No

  BSD Name:          disk0

  Medium Type:          Rotational

  Partition Map Type:          GPT (GUID Partition Table)

  S.M.A.R.T. status:          Verified

  Volumes:

disk0s1:

  Capacity:          209.7 MB (209,715,200 bytes)

  BSD Name:          disk0s1

  Content:          EFI

Machintosh HD:

  Capacity:          3 TB (2,999,733,223,424 bytes)

  Available:          1.62 TB (1,617,339,432,960 bytes)

  Writable:          Yes

  File System:          Journaled HFS+

  BSD Name:          disk0s2

  Mount Point:          /

  Content:          Apple_HFS

  Volume UUID:          7AEFC0EC-7776-3464-A76D-61EF15F3954E

Recovery HD:

  Capacity:          650 MB (650,002,432 bytes)

  BSD Name:          disk0s3

  Content:          Apple_Boot

  Volume UUID:          71B47D8C-035A-3468-84AC-C8E1C8B45DCA

Well I did the zeroing-out. It ran through without issues. Reinstalled Mountain Lion. No problems.

Info from Disk Util:

Name : WDC WD30EURS-63R8UY0 Media

          Type :           Disk

          Partition Map Scheme :           GUID Partition Table

          Disk Identifier :           disk0

          Media Name :           WDC WD30EURS-63R8UY0 Media

          Media Type :           Generic

          Connection Bus :           SATA

          Device Tree :           IODeviceTree:/PCI0@0/SATA@1F,2/PRT0@0/PMP@0

          Writable :           Yes

          Ejectable :           No

          Location :           Internal

          Total Capacity :           3 TB (3,000,592,982,016 Bytes)

          Disk Number :           0

          Partition Number :           0

          S.M.A.R.T. Status :           Verified

          Raw Error Rate :           000000000000

          Spinup Time :           0000000023CE

          Start/Stop Count :           00000000004C

          Reallocated Sectors :           000000000000

          Seek Error Rate :           000000000000

          Power-On Hours :           00000000006F

          Spinup Retries :           000000000000

          Calibration Retries :           000000000000

          HDD Temperature :           00000000001A

          Reallocated Sector Events :           000000000000

          Current Pending Sectors :           000000000000

          Offline Scan Uncorrectable Sectors :           000000000000

          CRC Error Rate :           000000000000

          Multi-Zone Error Rate :           000000000000

I beleive if the drive was flaky, I'd be seeing an awful lot less zeros here.

Thinking about it, when I was moving stuff over from my flaked-out old Seagate (through FW800), OSX actually FROZE once during copy, and I had to hard reboot the thing. That may have been the culprit.

There are other users that are likely experiencing symlink corruption on the following thread:

https://discussions.apple.com/message/20106545?ac_cid=tw123456#20106545

The symptom they are experiencing is manifested in Mail.app.  I'm experiencing the same issues with Mail.app and have identified numerous corrupted links in the ~/Library/Containers folder. For mail its in the ~/Library/Containers/com.apple.Mail but I went ahead and looked through the entire parent and found corrupted links throughout.

Just more data for the fire.

J

Okay, no freezes this time, just a bunch of links getting corrupted wholesale. Disk stats still report zero error rate.

This is getting on my nerves now, I wrote the service who did the HDD replacement if they have any idea what we could do about this. It's not the links, sure that's a problem too, but I can no longer trust the bloody thing with sensitive data like video, audio or books, what if those are next.

I'm planning of selling the machine now, hopefully the average idiot who buys it won't notice a thing out of the problem, and I'll try grabbing a newer model.

IMPORTANT!

I have an idea. Please everyone who had symlink corruption, post the SIZE of your root file system! I'm starting to suspect a problem with "too large" volumes, maybe an integer overflow of something similar.

Mine is 3T.

Also, I'm trying something new. I'll move the entire Users folder to a secondary slice formatted as ZFS using Zevo. Since ZFS is extremely robust, I expect it will catch any disk error... And first of all, I'll boot in a Linux rescue cd, and run badblocks -w on the entire disk.

We are running a 4TB Raidset. We split it up into a 500 GB Root and two 1.6TB Data partitions, but that didn't help.

Iosepho wrote:

 

IMPORTANT!

I have an idea. Please everyone who had symlink corruption, post the SIZE of your root file system! I'm starting to suspect a problem with "too large" volumes, maybe an integer overflow of something similar.

 

Mine is 3T.

 

Also, I'm trying something new. I'll move the entire Users folder to a secondary slice formatted as ZFS using Zevo. Since ZFS is extremely robust, I expect it will catch any disk error... And first of all, I'll boot in a Linux rescue cd, and run badblocks -w on the entire disk.

Interesting idea - I hadn't thought of that!

On the machine where I am having symlink problems, everything is on one 3TB disk (no partitions, just one 3TB partition spanning the whole disk)

On the machine that seems to be problem-free (laptop), my hard drive is 1 TB, but it is split into two partitions; a Mac partition of ~600 GB and a Windows (Boot Camp) partition comprising the rest of the drive.

Perhaps you're on to something here...

Mine root filesystem is 4T single SATA drive, manufactured by Hitachi.

I've just downgraded the drive to a 2T drive; it's been running for 3 days with no problem, so perhaps you are on to something.

marcos

3TB hard drive here as well.  The 3TB upgrade from a 1TB drive occurred around the same time I upgraded and started seeing issues.

Jeff

I initially saw it on a 2TB drive and again saw it on a 3TB drive I replaced it with.

I've installed Mountain Lion on about twenty Macs. The only one I have seen the sym link corruption rather reguraly is my iMac which has a 3TB drive. All the other Macs have 2TB or smaller drives and have had no issue. It very well may be a bug with large filesystems. HFS+ really needs to be replaced with something more modern.

I suppose we're waiting for Apple to come up with a fix.

Here's a "me, too."

One of my clients has a Mac Pro 5,1 with Apple RAID Card creating a 3.6TB volume that we boot from running 10.7.5.

Their initial issue centered around a MySQL database not backing up (/usr/local/mysql symlink was broken).  But in the course of that we saw Apple apps not opening, crashing...  Since discovering this thread, I replaced broken symlinks by comparing a list of their symlinks with those of a fresh install of 10.7.5 and it appears to cure all ills... for now.  There were a lot, mostly in /System/Library - but the /usr/local/mysql symlink may be interesting because that's not part of the base OS install.

As you might expect, the broken symlink is backed up via Carbon Copy Cloner and Time Machine (so your backups are screwed too unless you catch it quickly enough to find a good symlink in archived deltas).

The big volume theory is interesting enough for us to try and test against that.  Will report back if I find anything.

Here's hoping for 10.7.6 and/or 10.8.3.

Did you partition these in Disk Utility (so they are disk1s0, disk1s1, disk1s2) or in the RAID card (so they are disk1s0, disk2s0, disk3s0)?

Brian Best wrote:

 

Here's a "me, too."

 

One of my clients has a Mac Pro 5,1 with Apple RAID Card creating a 3.6TB volume that we boot from running 10.7.5.

 

Their initial issue centered around a MySQL database not backing up (/usr/local/mysql symlink was broken).  But in the course of that we saw Apple apps not opening, crashing...  Since discovering this thread, I replaced broken symlinks by comparing a list of their symlinks with those of a fresh install of 10.7.5 and it appears to cure all ills... for now.  There were a lot, mostly in /System/Library - but the /usr/local/mysql symlink may be interesting because that's not part of the base OS install.

 

As you might expect, the broken symlink is backed up via Carbon Copy Cloner and Time Machine (so your backups are screwed too unless you catch it quickly enough to find a good symlink in archived deltas).

 

The big volume theory is interesting enough for us to try and test against that.  Will report back if I find anything.

 

Here's hoping for 10.7.6 and/or 10.8.3.

Now that I think about it some more,  my problems seem to have begun when I upgraded my Mac Pro from a 1.5 TB drive to a 3 TB drive.  So the big volume theory could very well be plausible.