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Raw & Post Processing, Printing => Digital Image Processing => Topic started by: Nill Toulme on September 08, 2006, 01:34:37 pm

Title: XP NTFS disk compression - reliable?
Post by: Nill Toulme on September 08, 2006, 01:34:37 pm
Any reason not to let NTFS compress an external HD used for backup?

Nill
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www.toulme.net (http://www.toulme.net)
Title: XP NTFS disk compression - reliable?
Post by: DarkPenguin on September 08, 2006, 01:55:18 pm
If you're putting photos on it they really won't compress and you make things more interesting for recovery later on.
Title: XP NTFS disk compression - reliable?
Post by: Nill Toulme on September 08, 2006, 02:49:13 pm
Thanks.  It occurred to me belatedly that because 95% of my data consists of already-compressed RAW files, further compression is probably a waste of time...

Nill
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www.toulme.net (http://www.toulme.net)
Title: XP NTFS disk compression - reliable?
Post by: Jonathan Wienke on September 09, 2006, 05:59:24 am
Actually, it's not a waste; you'll get another 10% or so file size reduction with RAWs and JPEGs, and it doesn't make file recovery any more difficult. The compression is part of the OS, and is done on individual disk clusters, so the decompression is done before the data is sent to the disk recovery program and therefore file recovery is no more difficult than when working with uncompressed data. I've been using compressed NTFS personally and professionally for over 8 years, and its only downside is slightly higher CPU utilization while writing to the disk.
Title: XP NTFS disk compression - reliable?
Post by: jeffreyluce on September 09, 2006, 09:52:10 am
I thought this was interesting.... http://www.ntfs.com/ntfs-compressed.htm (http://www.ntfs.com/ntfs-compressed.htm)

Quote from the above link.
Quote
The compression algorithms in NTFS are designed to support cluster sizes of up to 4 KB. When the cluster size is greater than 4 KB on an NTFS volume, none of the NTFS compression functions are available.
Title: XP NTFS disk compression - reliable?
Post by: Nill Toulme on September 09, 2006, 12:09:51 pm
Quote
Actually, it's not a waste; you'll get another 10% or so file size reduction with RAWs and JPEGs, and it doesn't make file recovery any more difficult. The compression is part of the OS, and is done on individual disk clusters, so the decompression is done before the data is sent to the disk recovery program and therefore file recovery is no more difficult than when working with uncompressed data. I've been using compressed NTFS personally and professionally for over 8 years, and its only downside is slightly higher CPU utilization while writing to the disk.
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Wow, thanks Jonathan.  10% is definitely worthwhile in this situation.  I will give it a try.

Nill
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www.toulme.net
Title: XP NTFS disk compression - reliable?
Post by: Nill Toulme on September 09, 2006, 12:14:07 pm
Heh... when I told it to compress the disk, it started out saying "200 days and 14 hours remaining."  Once it took three minutes to deal with the first outlook.pst file, though, it dropped down to "8 days and 11 hours remaining," so I'm optimistic.  ;-)

Nill
~~
www.toulme.net
Title: XP NTFS disk compression - reliable?
Post by: Nill Toulme on September 09, 2006, 12:16:01 pm
One more question — is it OK to use a defragmenter, e.g., Perfect Disk or Diskeeper, on a compressed drive?  Well two more — is there any reason to?

Nill
~~
www.toulme.net (http://www.toulme.net)
Title: XP NTFS disk compression - reliable?
Post by: jani on September 10, 2006, 05:31:45 pm
Quote
One more question — is it OK to use a defragmenter, e.g., Perfect Disk or Diskeeper, on a compressed drive?  Well two more — is there any reason to?
Unless you keep on deleting and adding new files more or less at random on your compressed drive, defragmentation should be superfluous, unless there's something special about compressed drives that make disk utilization even worse than what's usual with NTFS.

But you can check that easily enough by running the Disk Defragmenter.

Basically, defragmentation should only worry you for disks that you need decent performance from. A backup drive hardly fits that description; you won't be accessing it often.
Title: XP NTFS disk compression - reliable?
Post by: Nill Toulme on September 10, 2006, 07:06:41 pm
That makes sense.  Thanks.

Nill
~~
www.toulme.net
Title: XP NTFS disk compression - reliable?
Post by: budjames on September 11, 2006, 05:07:30 am
I wouldn't mess with hard drive compression as it's not worth the risk.

How about upgrading your disk drive instead? Drives are cheaper than ever these days.

My Dell Precision workstation has an internal 320 RAID SATA drives. Using firewire800, I have 4 external drives providing another 1,800GB of storage about 800GB of that is used for backups of my image files.

Bud James
North Wales, PA
Title: XP NTFS disk compression - reliable?
Post by: Nill Toulme on September 11, 2006, 08:01:14 am
This is for a redundant offsite backup drive.  It's a 750GB external that backs up the two 400GB externals that are currently backing up my 1.1TB internal RAID5.

Nill
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www.toulme.net (http://www.toulme.net)