Linked by Thom Holwerda on Thu 13th Jun 2013 14:35 UTC
Mac OS X The third and final WWDC product I want to talk about is - of course - OS X 10.9 Mavericks. While iOS 7 was clearly the focus of this year's WWDC, its venerable desktop counterpart certainly wasn't left behind. Apple announced OS X 10.9 Mavericks, the first OS X release not to carry the name of a big cat.
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RE: Interested in compression
by darknexus on Thu 13th Jun 2013 16:35 UTC in reply to "Interested in compression"
darknexus
Member since:
2008-07-15

i trust NTFS more still (apart from the king which is ZFS).

I don't. When NTFS crashes it can be far more subtle, let's say a cluster bitmap corruption (i.e. the bit that tells the filesystem what space is used and what is free). Ever seen that? It looks, on the users' end, like files are randomly disappearing as they're being erased by new files without the os realizing it. Yes you can repair it, but you can't get the files that were replaced back again unless you have a backup, and if you're not watching it closely you may not notice this right away. It's nasty. At least when most other filesystems crash you know it and in some of them, like the ext? filesystems and zfs, it is self-correcting as there are multiple copies of the superblock and inconsistencies are checked against them.

Reply Parent Score: 4

RE[2]: Interested in compression
by malxau on Thu 13th Jun 2013 19:13 in reply to "RE: Interested in compression"
malxau Member since:
2005-12-04

I don't. When NTFS crashes it can be far more subtle, let's say a cluster bitmap corruption (i.e. the bit that tells the filesystem what space is used and what is free). Ever seen that?


So firstly, I work on Windows filesystems (see bio.) I get to see a lot...

It looks, on the users' end, like files are randomly disappearing as they're being erased by new files without the os realizing it.


I don't think this is what happens. Imagine a cluster is in use by FileA but (for whatever reason) the bitmap doesn't record it as allocated. Now FileB gets allocated the same cluster. FileA is still there, because the system didn't detect the condition. It's just that FileA's contents end up the same as FileB's contents, because they're using the same block. And if only one cluster was in this condition, the party stops here, because the cluster is now marked in use so only these two files will share it.

Given how bad this is, NTFS works hard to avoid it, both at the design level and by making pessimistic assumptions in event of detected corruption. As above, I see a lot, and I don't see this often.

...like the ext? filesystems and zfs, it is self-correcting as there are multiple copies of the superblock and inconsistencies are checked against them.


ZFS has checksums so it can detect corruption in its structures (assuming, of course, that the corruption was not generated by a bug), and use a good copy if one exists. ReFS, Microsoft's next generation file system, also checksums its metadata, and when used with Storage Spaces can also locate a good copy of data if one exists. Ext2/3 do not. Ext4 checksummed its journal and more recently metadata too; I don't know how it would be able to recover though, since AFAIK it doesn't keep redundant copies, so it has nothing to recover from.

Reply Parent Score: 5

rekabis Member since:
2010-02-25

I don't. When NTFS crashes it can be far more subtle, let's say a cluster bitmap corruption (i.e. the bit that tells the filesystem what space is used and what is free). Ever seen that? It looks, on the user's end, like files are randomly disappearing as they're being erased by new files without the os realizing it.

Given how bad this is, NTFS works hard to avoid it, both at the design level and by making pessimistic assumptions in event of detected corruption. As above, I see a lot, and I don't see this often.


I have been working with computers since 1982, on the Internet since 1988, on the Web since 1992, and in the I.T. sector since 1997. I have enjoyed the Windows NT line of computers ever since NT 4.0 was released (got my first copy late 96), and I have *NEVER* seen something like this happen. And I have repaired thousands of NTFS-based Windows computers and Windows installations in my day from 4.0 clear up to Win8.

Was I just lucky? *knocks on wood*

Edited 2013-06-13 20:29 UTC

Reply Parent Score: 3

REM2000 Member since:
2006-07-25

i have to agree with the other posters, i haven't seen this problem myself, ive been using NT since 4, since about 1998.

The worst ive ever seen an NTFS volume was on a windows 2003 server, i can't remember what brought it about, either a problem with power or something, but it seemed pretty corrupted, however after a couple of automatic restarts after a chkdsk during start up it went along fine, couldn't see any data loss on the drive either which was surprising.

Ive seen some pretty bad use of disks on windows, unplugging when files are copying, powercut/power cycling, but NTFS always bounces back.

Reply Parent Score: 3