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Compression on NTFS Virtues and Pitfalls

is it too risky to compress an NTFS HDD i got most mp3 files on it thanks
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Pete Long
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Hello There


Just use windows compression on the folder your MPS's are in

Best Practices for NTFS Compression in Windows
http://support.microsoft.com/default.aspx?scid=kb;en-us;251186

PeteL
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Dalziel

Hello,

NTFS isn't really your limiting factor, regarding compression. The two main types of compression are "lossy" and "lossless", lossy removes bits of data that it's assumed you don't need, MP3's (chiefly) do this, thus the sound quality goes down. Lossless reorganises the data into a more efficient form for storage, thus taking up less space. The downside is that since the data is still there it takes up more space than a lossy compression and more time/CPU cycles to open/decompress it again. Generally you mix the two.

The main risk with a tight form of compression is that a small amount of corruption can really mess it up due to the tightly bound data, thus making retrieval difficult. Actually the NTFS way of working, when compared to the older systems, is far more reliable in this respect.

My point is that with MP3's you have already compressed it and thus lost some of the sound quality. You can get it a lot smaller sure, but it depends on how you do it. That said the built in Windows one should be fine for limited compression as long as you have backups of the stuff that's important. Compressed or not compressed if it's all on one disk - it's at risk.

Regards
Dalziel

 

> is it too risky to compress an NTFS HDD i got most mp3 files on it thanks

Yes:

1) makes the files too incompatibe in too many ways
2) makes file access too slow

No:

1) Files are smaller, so you can save space, load even more files
2) The risk of losing them is not that great, and anyway, HD is not for permanent storage of all those files

I've heard some claim the sound quality etc is just as good, others claim there's too much loss. To each their own ears, so for my

Answer: Try it out, see which you like best

a) make one that is compressed
b) make one that is not compressed
c) place same sample file on each, review both space and evaluate quality issue
d) choose
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SysExpert
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You'll find compression to be a pain. Access to compressed files is slow and you'll probably never get to uncompress them again if you wanted to because you need heaps of free space to be able to do so.
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Yeah I agree with both SysExpert and talkiet, MP3's are already compressed so you won't get back much space unless you use a heavy and possibly lossy form of compression, which will just take more time and trouble. CD's, and the writers if you don't have one, are amazingly cheap, even by computer depreciation standards, you can get tens of GB of storage for next to nothing, plus your data will be safe when, yes when, your machine crashes.

Regards
Dalziel
I think what they are trying to say is that compression won't help much with already compressed files.

Risk.  Get real. It's the same risk that you have with all files on an NTFS or FAT32 drive ( yeah, you can't compress files on a file by file basis like you can in NTFS.)  
Point #2: Its lossless compression. Compressing a MP3 file will NOT make it sound worse. Yeah, it might stutter if your drive needs defragmenting or is just a poor performer.
I agree with most of the above - it is normally not worth compressing an already compressed file.

However with NTFS compression is is definitely not worth it. NTFS compression only works if it can save an entire clusters worth (or more) of space - so even though the NTFS compression algorithm may make a little difference it is highly unliklely to make enough difference with an MP3 file.

There is a white paper here http://www.sandersonforensics.co.uk/Files/NTFS%20compression%20white%20paper.pdf that explains how NTFS compression works

HTH
Paul
Risk. Your files compressed on a NTFS volume are at no more risk than the rest of your files. That's the answer simply. Speed. Unless you have a pokey 133 to perhaps a 400mhz system, you will not really notice any performance difference unless you are using MASSIVE database files that you are trying to use.  Compression can actually improve performance under certain circumstances since the files are moving across the bus in a compressed format. Files that compress excessively well and that are big such as large bitmap files may see performance gains from compression- especially when reading.  On todays 2.0+ GHZ machines, the compression penalty is neglible except when copying numerous files into a folder since compression copies the raw file in first and then recopies the file as NTFS compresses the file.

Compressing certain types of files makes sense - files such as mostly text files such as .txt, doc, rtf, etc... Bitmap files and uncompressed tiff files are also good candidates.  Any format that is already a compressed format of file such as jpg, gif, mpg, mp3, etc are a waste of time to compress and sometimes can result in performance penalties and the files can actually grow in size due to the compression process.

Clusters: Sandy771- NTFS will actually store a file uncompressed even if the compression attribute is checked and if the file already fits within a cluster. - It's smart enough to realize there will be no savings!   I really think that most MP3 files are larger than a cluster. On NTFS, on my 160GB drive, the cluster size is 4Kb- the default size. So most MP3 files would span at least a cluster.

Pir84Free

Thanks for the info re clusters - if you have alook at the white paper on my web site above, you will see that this is dealt with there.

Paul
Sandy771: While your article-link gives an in-depth look at compressed files on NTFS, it's probably more in-depth than most could comprehend or would want to.  It twas interesting none-the-less.

Are compressed files non-recoverable ? Whether they are or not, it's just good sense to make a backup copy to cd-r or dvd-r, just in case.

Re-reading: incompatible- no- NTFS compression works at the system level, not at the application level, so NTFS will not make some files incompatible. If you have applications trying to write at the system level, you'll end up with the system crashing anyways.  

Really, though, the answer to this question has been covered from nearly every perspective and should be enough for dilip2k to make an informed decision.   Right answer: Well, most of the feedback has been excellent.