-40 File Positioning Error

[JStrickland]

I have a Retrospect Client machine running MacOS 10.3.9, and client version 6.0.108. Retrospect Server is version 6.1.126 on a Mac running OS 10.3.9. Lately, when backing up this client, I am getting a -40 "File Positioning Error" on a file called .hotfiles.btree. I am not exactly sure what this message is telling me, and I can't find any info on the knowledgebase. It is likely that the file is corrupted?

[waltr]

hi j,

 

i did a quick google search and found some good info on the .hotfiles.btree files here:

 

http://maczealots.com/articles/hiddenfiles/

 

here is the relevant part:

Quote:

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.hotfiles.btree

This file is new to 10.3, as is the feature that uses it. 10.3 introduced a technology called "Hot-File-Adaptive-Clustering" (HFAC) that will do two tasks to improve the system:

 

Whenever you open a file less than 20MB in size, HFAC checks it for fragmentation. (Files larger than 20MB will need to be defragmented by a 3rd-party utility such as Norton or DiskWarrior. If HFAC finds fragmentation, it repairs it automatically and moves the entire length of the file to a sector on the hard drive big enough for the file. The old storage sectors are then erased and declared empty for use again.

(NOTE: For those of you that make use of Panther's government-approved "Secure Delete" option when emptying the Trash, this most likely does not apply that. Remember that a normal file deletion merely removes the reference from the file directory; the data is still there. Thus, the same can probably be said for the locations of the once-fragmented file pieces.

HFAC also seems to be moving frequently accessed files to the fastest part of the hard drive (presumably the inner rings) for faster access times. This frequency would be measured over multiple restarts, longer than virtual memory would store frequent data.

 

This brings us to the purpose of the .hotfiles.btree file. A B-tree file stores the file directory so the system can access a file when requested (read more on the immense coolness of B-trees here. This file most likely stores the file directory of the "hot files" stored on the inner rings of the hard drive for fastest access. The directory is maintained here separately for easy (and fast) access.

 

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it seems to me that these files may be corrupt, or they may be in use during the backup. since this has happened multiple times, they are probably corrupt in some way. the article gives a technique to make them visible, and you could delete and reboot the machine in question without any problems i suppose (but you should check into this more before doing anything drastic--i'd suggest using 'Disk Warrior' as your first step, and hitting the web while that's going on).

 

if you don't want to do that, you could also add these files to an 'exclusion' section of your selector. you may, however, still see the error if it is happening during scanning, rather than the copy phase of the backup.

[waltr]

quick follow up: wondering what would happen, i opened up a Terminal and became root, deleted the file, and rebooted the computer. the file has been recreated and i don't see any problems so far. i'm running 10.4.2 Desktop here.

[JStrickland]

Thanks for the info. I was so focused on the error message I didn't even think to do a search on the file being affected.