[mythtv-users] Changing filesystems?

[William Powers]

Ok, now I'm replying to myself...

The mkfs.ext3 problem was caused by some peculiarity in the partition 
table.  Deleting and recreating the partition fixed it.  It did not, 
unfortunately, fix my XFS 4G problem...

With the mkfs.ext3 problem fixed, I was able to confirm that it does 
take longer to delete a file on an ext3 filesystem when that filesystem 
was formatted -T largefile4.  Two instances of deleting a 10G file on a 
filesystem formatted 'mkfs.ext3 -m 0' resulted in times of 1.4 and 2.3 
seconds.  Two attempts at deleting a 10G file on a filesystem formatted 
  'mkfs.ext3 -T largefile4 -m 0' took 5.9 and 10.2 seconds.

 From this I would personally conclude that, if you want to use ext3 for 
your video partition, the extra storage space I get by formatting '-T 
largefile4' (about 2G more available space on a 100G partition) is not 
worth the substantial decrease in file deletion performance.

Now, if I could just figure out my XFS problem...

Bill

William Powers wrote:
>  >> Based on that, I ran an experiment to compare the deletion time of a
>  >> single 10G file on an ext3 partition and on a JFS partition. The
>  >> results were 10.2 seconds to delete the file on the ext3 partition
>  >> and 0.9 seconds to delete the file on the JFS partition.
> 
>  > You didn't by any chance do the same test with ReiserFS did you?
> 
> I did not test anything except JFS and Ext3 the first time around,  but 
> I have since tried to do a slightly more comprehensive test by 
> attempting the single 10G file delete test for all five of the relevant 
> file systems.  However, I had some issues and wasn't able to complete 
> the full test as I had planned, this on an RHFC1 system with the Myth 
> components installed via ATRpm's.
> 
> JFS:  Repeated the 10G file delete and got 0.9 seconds again
> 
> ReiserFS:  Got 6.2 seconds for the 10G file delete
> 
> Ext2:  Got 1.6 seconds for the 10G file delete
> 
> Ext3:  For some unknown reason, I was not able to (re)format the 
> partition using 'mkfs.ext3 -T largefile4 -m 0 /dev/hdb4' as it was 
> originally without encountering a floating point exception.  After 
> formatting the partition using 'mkfs.ext3 -m 0 /dev/hdb4', I repeated 
> the 10G file delete and got 2.3 seconds.  At this point, I have no idea 
> why I was unable to use '-T largefile4', nor do I know whether the 
> apparent difference in times between partitions formatted with and 
> without 'largefile4' is significant.
> 
> XFS:  For some reason, attempting to write a 10G file to the XFS 
> formatted partition locked up the PC (hard) at about the 4G point, each 
> and every time.  So I am unable to perform the 10G delete test with XFS 
> unless and until I find out what my 4G problem is.
> 
> So, that is where things stand at the moment...
> 
> Bill
> 
> 
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