[mythtv-users] File System Recommendation?

[Steven C. Liu]

Brian Wood wrote:

>On Apr 2, 2006, at 9:01 PM, Richard Dale wrote:
>
>  
>
>>>I'm using ext3 on a RAID-0 system. Who the heck cares if it takes a
>>>second or two to delete a 1-hour show ??
>>>      
>>>
>>Here's an interesting solution - the recording could be flagged for  
>>deletion
>>and then deleted in a background thread.  So, even if it takes a  
>>while it's
>>the background thread that has to wait on I/O, not the foreground user
>>interface.
>>
>>    
>>
>
>I don't know for sure how the kernel and ext3 handle these things but  
>I would *think* that the system is smart enough to not block on a  
>delete. I'd think the file would be marked as deleted in the cache  
>and the actual "deletion" (really just marking space as available)  
>would be carried out when IO was available.
>
>Or is that what makes the newer filesystems "better" ?
>
>I've certainly never noticed any delays even when I delete a dozen or  
>more shows rapidly, If I had I would have switched to another FS  
>(maybe).
>

Brian,

How you described it is how a filesystem works.  A write(3) and a 
remove(3) only causes the fileop to be cached and the inode to marked as 
"dirty".  The periodic sync then writes to disk and clears the "dirty" 
inodes.

JFS is a journaling fs, which means (at least to me) that fileops are 
recorded in an index for that filesystem and your view of said 
filesystem is in the form of "snapshots".  Writes and deletions are 
merely record changes in a specialized database.

Steve
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mythtv.org/pipermail/mythtv-users/attachments/20060402/50eea87c/attachment.htm