On 4/8/2010 9:48 AM, Norbert Schulze wrote:
>> Raid5?  That has horrible write performance,
>
> It is a RAID50
>
> IMHO: BackupPC_nightly mainly reads from disk!?

It traverses the pool directory, stat()'ing each inode (which isn't like 
to be near the directory) looking for entries that only have one link, 
meaning that all of the pc backups that previously linked to it have 
expired, and deletes these files.  The deletes involve small writes back 
to the directory, inode, and free space list which will be slow as the 
raid5 must do a read before the write and then update the parity, 
essentially tying the speed to the slowest disk.  How many of these you 
do will relate to the turnover of files on the targets.  If you do a 
large number of maildir type folders with a lot of activity there could 
be a lot.

-- 
   Les Mikesell
    lesmikesell AT gmail DOT com

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